The cloud is always stupid expensive compared to running your own hardware for almost any sort of task that isn't highly variable upon one or more axis (cpu, ram, etc), but less than a week to break even is truly shocking.
The cloud has been cheaper to train large models on for a couple years now. Compare buying 8xA100 server vs renting one on Lambda Labs. At least 3 years to break even - if you are using it non-stop 24/7. Longer if not.
