Gresham's law really only applies when there are efforts to peg the market price of a crappy money vs a better money.
Their's law says good money drives out bad when there is fairly open competition (& eventually even in controlled economies).
Discussion
This is the biggest hurdle for techies. Bitcoin looks like a technology at first impression. They think it will be succeeded by the next version.
That’s why they’re so confused when the community won’t let them “innovate” and fill the codebase with their tech debt. 😀