What's stopping the Avengers from using time travel again?

They can make more Pymm particles and they still have the tech. Next time a villain decimates the population, what's stopping the Avengers from hitting reset again?

Edit: To clarify: what's stopping them from going back in time to borrow the stones from Cap real quick to do a new snap and resurrect the dead. Basically, the Avengers have Dragonballs now.