[Anon826]

Successful UK companies don't manage to reach anywhere near that because the owners/shareholders usually get a juicy offer from non-UK buyer and prefer an easy payday rather than further developing their company/products internationally. There's too many successful food companies bought by US companies in the past 30 years, the latest being today Mars (USA) buying Hotel Chocolat (UK) for £534m.

In Europe the nationalism/laws in Germany and France is very high so it doesn't happen as often. That's why you see UK selling Rolls Royce (to German rival) and Jaguar and Land Rover to India. The opposite will never be allowed to happen. The UK politicians allow it to appease foreigner rich folk and hope they love Britian in return (they don't). Prime example is the sale of ARM in 2016.

If one reads Bloomberg/FT they regularly go on how UK public companies are a great buy given their shares are low but their dividend payouts high, but international investors do not invest for unknown reasons (because UK is regarded as a sh*ithole). So the current marketcaps of UK companies should in fact be much higher if they had the proper investment by international investors like they do to other countries.