You say all this like it's a bad thing, but maybe it's ultimately better for a society if there isn't a financial lottery that enables a small number of people to become insanely wealthy and powerful.
I'd rather a government that enables a thousand mid-sized companies with moderately well-paid executives and employees than one that enables a single monopolistic mega-corporation with billionaires whose power rivals states and whose incentives are not aligned with most of the world.
Of course it is a monumentally bad thing for the UK economy it doesn't have any big tech companies! I actually don't understand your point at all.
To say nothing of the lost revenue from tech export do you think it is better for the UK that it depends on AWS cloud for running the majority of its public services, Apple for almost 70% of the phones used by it's citizens, Google for the other 30%?
Which midsize company is going to be able to compete with AWS on offering cloud computing services, Apple on developing smart phones or Nvidia on GPUs?
Actually the UK has the worst of both worlds: US big tech opens office here leading to well-paid executives and engineer, while all revenue (and none of the taxes) from selling the products these engineers develop goes to the US.
I'd rather a government that enables a thousand mid-sized companies with moderately well-paid executives and employees than one that enables a single monopolistic mega-corporation with billionaires whose power rivals states and whose incentives are not aligned with most of the world.