For a long time now, I've been eagerly anticipating the day my top anime rankings reach the nice round number of 200 entries. This winter saw three new entries to my rankings, which now sit at 189. At this rate, then, I'll reach 200 entries sometime next year. Whenever that time comes, once it comes, the top anime rankings will stay at 200 from there on. There's certainly a place to praise really good anime that just happens to be worse than 200 other franchises, but that can be listed under the runners-up label that sits just below the rankings. That's what being a runner up means, you aren't paid the special attention that the winners get, and being in my top rankings means you should be a winner. 201st at anything doesn't sound like winning.
The top 200 anime franchises are must-see, so it also needs to actually be seeable. I can't have people dying of old age before they get through my list, so there has to be a limit. 200 is the perfect round number to draw the line. For avid fans who want to watch more, there's always the runners-up list.
If a new series impresses me, after my list has already reached 200, I'll have to kick out a previous show that used to be ranked. They'll be 'motto espada' and designated as such in my runners-up list, but no longer espada. That's how time moves on and the world progresses. You can be the strongest ship in the sea until ironclads are invented, and then you're not worth talking about at all. So long as anime continues to improve, the same will happen even to our best art. That's a good thing, that's what should happen over time.
The highest ranked anime that debuted in 2013 is #52 Non Non Biyori, the highest ranked anime of 2014 is #50 Shirobako, the highest ranked anime of 2015 is #58 Hibike! Euphonium, the highest ranked anime of 2016 is #69 Hai to Gensou no Grimgar, and the highest ranked anime of 2017 is #85 Youjo Senki.
As you can see, anime hasn't exactly been on fire since 2012. Which means truly good series have nothing to fear from new series replacing them anytime soon. Maybe Clannad and the like won't be must-see tv in the year 3,000, but they've got nothing to fear from this century. Keeping shows at 200 will instead just give me a chance to prune weaker entries and raise the average quality of my top anime rankings list, which will make all the shows look more attractive. (You are who you beat).
Likewise, my manga hall of fame currently has 99 entries. It needs to reach 100, but after that it will stay at 100. My good authors hall of fame will stay at 100. My visual novel companies, video game franchises, and movie franchises/genres are all at top 50 and will stay that way. My top 10 tv hall of fame will stay that way. I'm fine with my great voice actors list reaching 200, though, to match my anime rankings. Currently at 119, there's plenty of room for growth there. But by next year, unless you're a seiyuu, anyone who wants in my hall of fame will have to kill someone else and take their place. It's nice to be inclusive and praise lots and lots of people, but there's a limit to human lifespans and thus a limit to human consumption. Nice round numbers are important too. Combine these two needs and my halls of fame are about maxed out. Like Cell, they've nearly reached their perfect forms.