Tech companies in Silicon Valley are ageist. The median age of workers at Facebook and LinkedIn is 29. At Google it is all of 30. “Young people are just smarter,” as Mark Zuckerberg is supposed to have said. And even if they are not smarter, they are certainly cheaper.

There are lots of stories of tragic people in their 40s and 50s buying hoodies and boning up on superheroes before they pound the virtual pavements in search of a job. Some eventually get hired, but most appear not to. It all reminds me of the things women have been doing for decades to try to fit into a male world — wearing trouser suits and taking up golf, only this time it is worse. San Francisco has become a hotspot for Botox, with tech workers in even their late 20s and 30s seeking to inject their faces with stuff that renders them expressionless, to fit in with their baby-faced colleagues.

Yet there are bigger barriers to older people working in tech that no one is talking about and which no hoodie or syringe full of botulinum toxin will take care of. It has nothing to do with any prejudice that the over-40s are slow at mastering technology or that they lack entrepreneurial spirit. Instead, the barrier is the very thing that these companies are being praised for: their new organisational structure.