Ethereum bought or will buy Polygon in the nearest future
Why do you think so?

Because it will be on ETHs mainnet, I think that's the reason for him. And if that's possible, it should have been done long ago when Polygon wasn't that big yet. But I think on its current state, it's quite big already and it's been noticed globally and the market share that it has got is quite good enough. Anyway, this is the crypto market we've seen acquisitions after acquisitions. And for a big crypto to purchase another project is possible but I don't think that it will happen anyway. As for this update[1] of Polygon, it's now live.
[1]
MATIC to POL Migration Is Now Live. Everything You Need to Know.