[karmakaze]

A lot of this has to do with the 'softness' of software. In the past, software was developed, shrink-wrapped and sold in physical media from warehouses and store shelves. The cost of bugs and errors was much higher and could result in software failing to gain adoption, or costly updates having to be prepared and physically shipped on floppies or CD-ROMs.

Video games is the most recent to undergo this transition. Up until not too long ago, physical DVD or Bluray media was the standard distribution mechanism. There were downloadable patches available post launch, but their sizes were originally somewhat limited to the write storage capacity. Now digital distribution with broadband connections is very common.

The softest of all are cloud software sold as a service. Any bug can be fixed for all users by updating the servers with a CI/CD deployment in sometimes minutes. With this increased softness, the product is always in development and there will always be new areas that have some usability issues as well as stable parts that have been worked out. But at any given time, there could be a fixed/large number of bugs if you were to count every one. Look in the reported issues for a popular repo that you thought was stable software--most of the time, most issues don't affect your use cases.

Long story short, it's what other comments say: it's economics and optimization. Of course there's also bad development and release policies which amounts to poor management or engineering culture, but I can't say that this is in excess to what's economical in my experience, except perhaps in the rare cases I ran away from.