Would have the opposite effect. Most of (but not all) the lower ranked teams are the one carrying old age bot players. Those nations would struggle even more.

I managed the Austrian National Side last season and spent most of my time trying to lower the average age of the team.

The current team has 49 players and 38 of those are in Bot teams and over half of those would have retired seasons ago if they where on a normal side and the remainder are pushing retirement age, and there isn't many Austrian teams to bring in new young players so if Bot teams had player retire the pool of National team would shrink to those countries with a player base to support that and that would basically mean an end to the group stages to reach the world cup, the group stages in the world cup and straight to the knock stage.

Maybe we need to change the training conditions instead, so that players over 30yo on bot teams are subjected to the same physical decline as any other player on active teams. This would at least have the effect of bringing some of these high-flying middle-aged NTs back to where they should be, while ensuring that they still have a reasonable pool of players to draw from.

Eventually, the players will get cycled out regardless. When they are on a bot team and the bot team falls to the bottom division in the region, they can be taken over by a human owner at any point. When this happens, all players from the old team are either deleted or put on transfer market. NT players are of course put on transfer market. At this point, a human owner must buy the player, in which case they will then start aging normally with stats declining. Should the player go unsold, he will be deleted after the second pass through the transfer market regardless of whether he's on a NT.
So, yes, we do get some players on bot teams that seem ageless, but eventually they will get phased out.
However, as others have pointed out, teams that have few players to draw from would be very seriously hurt if all bot players were eliminated. Some seem to have a hard enough time fielding teams as it is.