"For every complex problem, there is a solution that is simple, neat, and wrong."

Miners can just put 100 BTC TXN fees in their blocks— they're paid back to the miner after all, it costs them nothing but the risk that someone will reorg the chain to steal their block.  Also why "50"  by fixing 50 in the system you end up creating price distortion.

I had made a off the cuff suggestion which was similar to your motivation there but lacked these risks:  Set the new maximum blocksize to the median of the prior sizes multiplied by half the change in difficulty for increases in difficulty and by the full change for decreases, clamped to no smaller than 1MB. The idea is two fold: it's a cheat-proof way for miners to prove that an increase in size won't break the fee market because they have to work increase computing power to increase it,  and it indirectly measures the progress of silicon: if computers are twice as fast per unit energy, difficulty should be twice as high ... and boring nodes could hand 25% more transactions.  "If miners think that security can be maintained by increasing blocksize, then let them prove it by putting in more hashpower".

I don't like it because it only addresses the security spiral to the bottom problem. It doesn't address concerns about censorship, mining consolidation, enfranchisement of the users, etc. very much. It's also moderately complicated to understand.  It's also not realistic until mining is primarily on modern asics otherwise it will overly measure the change in technology type rather than the returns on mining.

My home was heated for two winters with mining. It is not the most energy efficient form of heating, if you ignore the mining income. But mining income is real and in very cold climates heat-pumps are not as effective. Ground loop for non-air heat sources for them are costly to install, etc.