But why do we, as society, grant them that right?

I mean, this is the reason why patents were invented originally: You publish the way your technology works, in return, after a short term, everyone can use it, which improves innovation.

Yet, nowadays, a lot more is done via trade secrets.

It would be awesome if we could get that innovation back that we’ve lost.

Because "we as a society" have no business telling other people what to do with their things as long as they don't hurt others.

For some people the alternative to closed source isn't open source, it's either "not publicly published" or "not developed at all", which actually slows development down.