GPU clouds use long term reserved cloud contracts as lock-in. Lambda started off kind of bragging about shorter term contracts on their website and then changed that to one year after the demand picked up (and investors piled in tons of money).

https://lambdalabs.com/blog/voltron-data-case-study-why-ml-t...

"While most other cloud companies offer contracts starting at one year, you can reserve a Lambda Reserved Cloud Cluster starting at six months."