Power corrupts, end of story. Democracy (limited terms), taxation and anti-monopoly regulation are examples that show a path to cure the disease. Nobody should be trusted with too much power for too long.
This could be quite good for competition, but would probably hurt sectors a lot that have high fixed costs/barriers of entry and need to compete with (foreign) unlimited-size companies.
I do think that this could fix or at least vastly improve some really difficult problems: The whole judiciary is IMO blatantly unjust right now, because higher wealth can basically buy you better outcomes, democratic representation is flawed because wealth/donations buy you access to politicians (or allows you to enter politics yourself) and even national public opinion on anything is essentially for sale to a degree via profit-driven media.
Such wealth-gap limiting could be possibly achieved by progressive taxation that rises logarithmically with revenue for companies and individual wealth (giving a strong incentive to split up wealth, and no leeway via declaring zero profits): Think 1% of revenue under 1M, 2% under 10M, ...
I'm very curious how a nation that made strong efforts in that direction would fare.