And what if you don't spend extra, will you not get an extra 2-3 BTC in fees because the others did?

Sorry if I'm not making sense, I haven't thought much about it and am just thinking out loud. If there are indeed incentives for collusion, wouldn't this be a long term solution to the security budget issue? They would be incentivized to spend even more for even higher block rewards, but not so much that Bitcoin becomes useless and loses value.