Those two events are causally related. The OS has to throttle down the CPU or else it will overheat and malfunction.
It is one of the reasons why heavy number crunching is often performed on the cloud instead.
Citation needed :)) There are economies of scale and various optimizations that are just not possible with dedicated machines.
Anecdotal evidence: a company I worked in had a dedicated DC with hundreds/thousands of machines that mostly ran SQL queries on petabytes of data (any query would take ~5-30 minutes). Eye-watering budget and whole teams to maintain the cluster... They switched to GCP/BigQuery, got queries that ran in seconds at a fraction of the budget.
Economies of scale go in the other direction usually.
Cloud hosting only makes sense in a case that your capacity needs are changing rapidly and unpredictably, or the case where you’re so big that the cloud hosting company is effectively a department. Any other time it will almost certainly be cheaper to self host.
Nowadays many cell phone application processors also have dedicated hardware to accelerate neural nets, but they will always be limited by thermal constraints.