I'd think it highly unlikely that the personal computer on your desk or the ipad I'm holding would exist if people hadn't rattled around carrying out seemingly crazy speculative and pointless speculation about quanta and cats in sealed boxes and stuff like that.

There might possibly have been some magnificent vast machines in government skyscrapers...

Most ideas turn out to be not quite true, often not at all true, but the turning out comes later. And often the ideas that turn out to be least useful are the ones that seemed patently true, and the crazy ones turn out to be the ones that turn out most useful in getting closer to the truth.