True, and I agree, but an 'upper cap' wouldn't be used against just the companies that we don't think provide innovation (such as Amazon in this scenario). The caps would also be used against Tesla and Apple, two very big drivers of innovation, and probably many others. The world would be a worse place without Tesla, and without Apple. Arguably the world could be a better place without Amazon, but that is surely down to consumer voting with their wallet, the executive team, and shareholders encouraging Amazon, rather than the government not restricting Amazon. Amazon aren't buying EA, only because they can.

Once again, how can someone define an 'upper cap', is it market size? Is it revenue, or employee count? Market share? The unintended consequences of an upper limit doesn't seem to me something we should be encouraging.

I could be wrong, it just feels like we shouldn't be restricting everyone because of one bad actor.

I think it depends. Bell labs famously invented many of the foundations of modern computing while Bell was a monopoly. It's also hard to do capital intensive research (e.g. semiconductor manufacturing) as an upstart. You need the resources of an Intel.

Meanwhile, companies that leverage existing technologies in new ways can be innovative with much fewer resources - e.g. your typical web startup.