Copyrights and patents should be reduced to a maximum of 7 years and then opened up for anyone to use it. Society will advance far more quickly and good business owners will be able to bring competition and lower prices to everyone.
The general theme here is a short half-life. You're advocating for shorter rollover - public domain after 7 years. I believe society needs a longer rollover.
I'd advocate for the lifetime of the original author, for the reason that I believe that the author of an enduring work should be protected by copyright for the duration of their influence _not exceeding_ their lifetime. My reasoning is the reality that most creative activity happens during the earlier stages of one's life, that creative people are often guided to less lucrative short-term outcomes for the promise of greater long term outcomes. It's the case of being compensated mostly in options, great for the long term if you have long term success. But also recognizing that long term success should not amount to infinite future benefit.
The only thing I can think of are things like novels. So the first Harry Potter novel was quite successful, but it took a while until a movie came out. Movie producers may be happy to wait until it came out of copyright. But that argument might be made for 15 years as well. It would be a different way of doing things, but not necessarily worse, I think. Is it reasonable that Disney can buy up the rights to all Marvel comic books for the last X years? Or would we prefer that anyone could make Marvel comic book movies after a short time -- even if that meant that the original authors aren't compensated.
Sometimes I think that even 5 years on software copyright is not a bad length. If you've been updating the software for 5 years, who wants to fork your project from 5 years ago? If you haven't, that's still pretty far out on the revenue tail even for something like enterprise software, let alone games, etc.
If you wanted a different rule for software then you'd have to carefully define what is meant by "software" and think carefully about side-effects: would you be discouraging people from releasing source code, for example? Perhaps not worth it.