> But I am wondering that if the prices drop so much, but the price to pay for that abundance would be the loss of significant part of job market, then how can we keep the economy humming ?

Money is an abstraction, so prices are always relative to wages. If prices go down, that's equivalent to wages going up. If your costs are $1000 and your wages are $1000, that's the same to you as if your costs are $100 and your wages are $100.

So the problem solves itself. You previously needed a job that would pay you $1000 to cover your costs, now you only need one that pays $100. And there is still $100 of work that needs to be done, because that's why things cost $100 instead of $0.