Arguably, if building quantum computers leads to quantum mechanics being falsified, that completely justifies the effort of trying to build them. The "disappoi

Arguably, if building quantum computers leads to quantum mechanics being falsified, that completely justifies the effort of trying to build them. The "disappointing" scenarios would be either that the engineering task turns out to be so hard that it stays "20 years away" for another century, or that quantum computers get built but nobody can find a really impactful and useful application.