True, but did you ever scale down an already setup & running dedicated machine? With dedicated hardware it's always like "if it works don't touch, and we might need it one day anyway" :)
I guess the point is if you own the machine, there is no reason to scale down, because you already paid the costs upfront. In conclusion cloud providers solve some of the problems they create in the first place very well ;)
Or in a more realistic scenario you forget to dial back an are paying $200/month extra for unused provisioned IO for years before anyone notices it. Happened, even though I was looking for improvements after every bill.