Hardware

Indeed. Current testing that measures just the temperature is basically the same as 20 years ago - when we had recent innovations like CPU shutting down the system when overheated instead of just frying itself. For the longest time when thermal throttling was introduced it was also very rudimentary - basically a binary situation between 100% performance or going down to like 25% when overheated with nothing in-between.

With modern CPUs pushing tons of extra watts for sake of marginal performance gains as well as precisely surfing the line of extracting vast majority of possible performance in given conditions it's just terribly inadequate.