Why are inactive players removed from the rankings?

It never made sense to me why players can be removed form the leaderboard due to inactivity. It's one of my biggest issues with how the rankings work at the moment.

For reference, I have a background in speedrunning, and when you set a time on the leaderboards, it's there to stay. Why doesn't it work the same way for osu? Why are player's achievements wiped from the rankings like they are?

I suspect many more players would take issue with this system if mrekk went inactive and akolibed became the #1 again, but this time by default. In my mind, it's still a big issue even if it's not for #1. Aetrna is top 50, Vaxei is top 100, etc. They got the pp, they deserve to be there until people pass them, no matter what.

Also, I hate when a ton of players get removed and it inflates my rank. I gained 23,000 ranks from the CSR rework, and I believe most of that is due to players being removed. I didn't earn those ranks. I'm not truly top 200k, but it shows it in my profile. I want to be compared against all players that have more pp than me, not just the ones that still bother to log onto osu. It's pretty annoying, and it's part of the reason why I don't really care about my rank anymore. It's just arbitrary when you remove people like that.

Not sure if this would ever be changed because a bunch of people would bitch about losing a ton of ranks even though they don't deserve to be ranked where they are right now. But imo, current system is dumb and players shouldn't be removed from the rankings due to inactivity.

TL;DR: Players getting removed from the rankings due to inactivity is dumb. They got to their rank through their effort, so they should stay there until people pass them. Current system inflates the ranks of many players for no good reason.