On the contrary, the system you proposed has been implemented many times over the history of Linux .. I can think of GoboLinux as an example, but I think NixOS also does this (may be wrong).
I prefer to just keep the system stable through careful application of well-curated dependency graphs. I've never run into any issue, having used Linux since the very first day, that I couldn't solve by proper application of package manager tools. It seems its easy for newbies and those who don't care enough to get into trouble, but with the right attitude you can easily have systems with years and years of uptime (personal experience).