This is happening to every industry. There is an obvious consolidation and massive wealth transfer still ongoing. Sickening
Easy enough to solve: tax wealth and redistribute it with a UBI.
These are extremely independent problems.
The problem with concentration isn't taxes, it's a regulatory environment that promotes concentration. You take money from Bezos, it doesn't change the size of Amazon.
A UBI would help some by making it easier to start a small business, but unless you address the underlying regulatory problems that give every advantage to consolidated megacorps, that's not enough.
One of the big problems is taxes though, specifically the taxation of dividends that get reinvested. Under the existing system, if you're Apple and you make iPhones and pay dividends to shareholders who invest them in a separate company that makes microprocessors, they pay more tax than if Apple keeps the money and makes its own microprocessors. And it works that way for everything, so corporations grow without bound and the tax system encourages that.
The easy fix is to make investment a tax deduction but sale of an investment fully taxable instead of only on the gain. We already try to do this in a hundred places, 401k and Roth IRAs and not taxing gains until they're realized, because it's obviously a good idea and promotes investment. But because we specifically don't do it in the case where you take profits from one company and invest them into an independent one, we've been promoting indefinite corporate expansion for decades.