It is time for the European telecommunications industry to think the unthinkable and abandon 3G - third-generation mobile telephony.

And that’s just one of the unthinkable thoughts that chief executives should be pondering as they head off for their summer holidays. Enough has changed in the world in the past two years to make it obligatory for any boss worth his underwater options to consider a completely different approach to business.

The decision by Spain’s Telefonica and Finland’s Sonera to abandon their joint 3G plans in Germany is the obvious signal to re-evaluate this ambitious technology. But merely pulling back from a clearly hopeless investment - outside the partners’ domestic markets - is not enough for the industry. Most wireless operators are still pressing ahead with domestic 3G plans, for which many have paid huge licence fees. Only the burst of fresh activity - in handset sales and service revenues - that the rich 3G experience will offer is seen as a solution to the industry’s malaise.

This represents a complete misreading of the future. Instead, networks should abandon the dream that handsets will become mobile media terminals, with lucrative content and e-commerce revenues. In reality, the wireless business will be what it has always been: communication between individual customers.

To offer that, even in a slightly enhanced way (for example, by allowing customers to transmit photographs) does not require the full 3G experience and technology, as Vodafone’s encouraging growth in low-technology data revenues, announced yesterday, demonstrates. A rational approach for a network operator would be to slash all 3G spending, to back out from its contractual licence agreements wherever that is possible and to focus on making earlier-generation technology such as the GPRS upgrades now available across much of Europe work properly. That means working in commercial terms not just technical ones, with comprehensible pricing and easy-to-use handsets.

Thinking the unthinkable on 3G would need to go further than just the network operators. European bureaucrats and governments - which have pinned their hopes on 3G to establish another European technological lead and are expecting future revenue streams and base-station roll-outs - would have to come to terms with the new shrunken reality. So would base-station and handset makers, such as Ericsson and Nokia, which are still hoping 3G will produce strong future revenue growth. Content producers - from film and record studios to news businesses - would also have to accept there is no 3G crock of gold. Think the unthinkable: turn off 3G.

Chief executives in other businesses have a few unthinkable considerations to ponder. For example, the pharmaceuticals industry may also have come to the end of the road it has been following for the past few decades. This can broadly be described as consolidation to achieve economies of scale in two dimensions. First, and most obviously, in distribution, the huge global sales forces in which a large part of a drugs company’s costs lie. And second, the hoped-for acquisition of new molecules that will produce the next blockbuster drug.

Both those two putative virtues are losing their appeal. Growing purchaser power, particularly under government auspices, is reducing the ability of the consolidated sales forces to generate real revenue growth. And the molecules are failing to become successful drugs with sufficient regularity, partly because big research departments turn out to be no more productive than smaller ones.

A new model for Big Pharma is urgently needed and it could be well worth spending some time poolside thinking of a new set of internal and external relationships - with customers, researchers, healthcare partners, regulators and governments - that could deliver a different approach, even if it meant reaching some unthinkable conclusion about size and likely future returns.

The holiday challenges for telecommunications and pharma bosses are really special cases of a bigger requirement for all chief executives to ask themselves previously unthinkable questions. The most far-reaching is whether the fundamental strategy of corporate growth, pursued since the 1960s, needs to be rethought. The notion of a growth company - raising revenues and earnings steadily, reinvesting a significant portion of those earnings in organic growth and acquisitions and benefiting from a price/ earnings ratio that reflects that projected growth - is so much a part of conventional thinking that we no longer spend any time considering alternative approaches. The telecoms and pharma examples fit this template perfectly.

But what if we start to use cash returned to shareholders not just as a means of valuing companies (as Lex has recently been discussing) but as the central purpose of corporate life? Under such an approach, freeing cash to be paid to shareholders would become the essential role of every manager.

Compensation and promotion would be linked solely to success in achieving this target. Share prices would be a residual number, reflecting cash distribution rather than substituting for it. The process would be a continuous one. Rather than simply returning cash to shareholders in an opportunistic way using intermittent buy-backs, companies would set up programmes designed to funnel cash continuously to investors in the most tax-efficient way.

Companies operating under such a regime would be much less focused on growth in revenues. Takeovers - other than ones immediately cash-generative through instant cost cuts - would dry up altogether. The emphasis would be on stable and predictable margins and on the proportion of those profits converted into cash.

Such an approach is not suitable for every company. But for many businesses, with stable technology and markets, it is much more appropriate than the conventional growth pattern to which so many have been shackled in recent decades.

In the middle of a sea change in the relationships between technology, financial markets, shareholders and managers, now is the time to tackle some of those unthinkable issues. And if you have trouble finding a suitable theme, I find those drinks with the little pink parasols have a remarkably liberating effect.