I think there comes a level where too much wealth/influence in the hands of an individual or a small group is bad for wider society.
Why?
Would the entrepreneurs who created these billion dollar companies/products not have created them if their individual persons wealth was restricted to say 100 million pounds or another nominal number?
More like would they have become billion-dollar companies in some case.
Though yeah that is a factor too for serial entrepreneurs Elon Musk's payout from PayPal was over 100 million - so what is he supposed to do next? You've just capped him from future investment. He can be an employee, sure.. or perhaps overseas a non-profit org or do charity work... but no Tesla, Space X, no funding for OpenAI etc..
Likewise no Gates foundation, no big pledges from Zuckerberg or Buffett.