What happens when the CPU cooler is removed?

Perhaps, I've formulated not exact enough. I was remembering what has been demonstrated in the famous video [1] for Athlon 1400 and 1200. Yes, the went not in flame but just in smoke. Back then the user was allowed to install a cooler direct onto the die though AMD CPU had no thermal protection (just thermal diode for emergency power-off the whole system by BIOS?). I have no confirmation for the following but I've considered that the pre-installed and hard and risky to remove the pretty massive heatspreader plate works not only as die physical protection but also as a minimal needed buffer for heat dissipation in case of rapid cooler removal. [1] "What happens when the CPU cooler is removed?" (Tom's Hardware Guide, 2001) ▶ this video link P.S. Another rather philosophical question I have since a ventilator (not just some heatspreader) was required for the first time for CPU to operate as advertised. Can one consider that CPUs are actually factory overclocked since then? Even though not to the absolute limit, e.g. Celeron 333A (@66) up to 500 (@100) manually.

That CPU will degrade over time when run at that level of heat. If Intel warrants their CPUs to be at TjMax 24/7, it's a good sign that it shouldn't be a problem. I have not heard of overheating killing CPUs since the days when AMD's didn't have any thermal protection[1], and I've cleaned out machines which were heavily clogged with dust and thermally throttling all the time for many years (the service prompted by their owners complaining about their computers being slow.) In one memorable case the push-in heatsink pins must've been originally not fully inserted, since they came out at some point and the heatsink was not even touching the CPU anymore, yet the CPU kept running for years in that state. [1] There's a famous TomsHardware video about that: ▶ this video

Yes, otherwise you end up with this: ▶ this video ;) (I'm well aware it's not a realistic experiment, but it's a fun demonstration nonetheless.)