In 2006 when the first aws instances showed up it would take you two years of on demand bills to match the cost of buying the hardware from a retail store and using it continuously.
Today it's between 2 weeks for ML workloads to three months for the mid sized instances.
AWS made sense in big Corp when it would take you six months to get approval for buying the hardware and another six for the software. Today I'd only use it to do a prototype that I move on prem the second it looks like it will make it past one quarter.