Current government already doesn't enforce contracts. Ex, prime video ads. Further there's no point in having contract terms if they can be changed unilaterally at any time.

Contracts are worth exactly as much as you're lawyered up and willing to get them enforced. There is absolutely still a functioning courts system to enforce contracts.

The one notable exception is if you're a group of workers and you negotiate a contract with your employer: the state can and will interfere to void it if it prevents the workers from being properly exploited.