Once they accumulate enough money most people stop working.

Yea, that leaves more room for competition. I've been to several countries where this is basically considered a good thing.

which makes everything cheaper

Food is less expensive in those countries. Ferrarri's are ungodly expensive. It makes designer goods cheaper. Not 'everything.' Demand is what makes things cheaper.

With people paid fully they do less work

You've lived in a monopolized economy for so long you literally are unable to think outside of it. You can have more than 3 cellphone companies. You can have more than 2 car companies. You can have more than 2 internet browsers.

It's like how a deflationary period sounds great on its face

It depends if you're holding debts or owing them. Most people owe money. The deflation would kill them.

supposedly 12% or something like that

A fucking tax rate "ideal?" lol. Based on what? Fantasy?