The original poster asked me what the downside were, and I just told you.

It is a very real downside, to me, and many other highly paid software engineers, that forcing us into collective bargaining agreements would result in us making significantly less money.

So thats the downside. It is very clear, and obvious. We would make less money.

So, given that we would make significantly less money, you can expect us to fight and sabotage efforts to force us into collective bargain agreements.

Good luck, you'll need it. Because right now, the anti-union side, in tech, is winning, and unions are not popular at all.