> Has it? CPUs ran much cooler back then.

CPUs now throttle to keep their temp in check. Back then, if the temp got too high they’d be permanently damaged like in the example above.

> Water cooling was harder. But also way less common or necessary.

Water cooling isn’t necessary today, either. The heat pipe heatsinks we have available are so good that you can cool every consumer CPU with a good air cooler. The automatic throttling means it won’t be a disaster if the temp gets high. Water cooling might get a few 100 more MHz during sustained all core workloads but it’s not necessary.