This is a bad idea, not only gives it loads and loads of extra work to the gms/devs/server maint people.
It also is terrible for players, say you have exams and the time to study + the time they take place makes you unable to play for a month. Your last exam is on Thursday (so a day after maint) and before that you are unable to log in for 1+ month, with your idea that person that studied hard and would like to finally play EE again will have to wait a FULL week before able to login again. (and that is only one of the many examples i can think of where you cant login for more then a month and would really want to play again when you finally can) If i was that person i would quit the game and find one where you can focus on real life for more then 2 weeks.
EE is a very casual game that you can easily play on and off when your time schedule allows you to play, it would be very bad to put a time schedule on a game like this.
1) It's not "loads and loads of extra work". It's a matter of several SQL procedures that should be written and rewritten. Then you launch them, and all the work will be done automatically.
2) If you are aware of the "1-month inactivity" rule, surely you can find time to log on for a few seconds once a month - no matter how busy you are. But you are right - there may be situations when you just have no possibility to log on for a month. Yet if you like the game, you won't rage-quit because you have to wait for an extra few days. Well, in a rare and unfortunate case you do have to wait a FULL week - if your month of abstinence has ended right after the maintenance.
3) It's a good thing that you care about the people who play occasionally. I care about them too.
But I do believe that situations like that described above are rare.
4) If the cause of lag is the tripled number of records in the DB, you won't normalize the situation with half-measures. You must either substantially decrease the number of records or you must substantially increase the access time to your hard drive, which is obviously not possible. EE team has already started the procedure of deleting players' accounts - with all the formalities and apologies, of course. Until now, it's the players who haven't played for 6 months and more. But will it be enough to solve the problem of lag? Nobody knows. Anyway, the period of one month that I suggested is hypothetical. It may be two months. Or three. And please, note one thing: I do not suggest to delete accounts, I suggest to reserve them - with the possibility of return. You said my idea is "terrible for players". Then what will you say about the EE team's idea of deleting accounts? Is it "wonderful for players"?
5) And finally - the problem of lag is serious, and it won't disappear by itself. You care about players - can you say how many of them will quit the game if the problem is not solved for another week? Two weeks? A month? How many players will continue to play in the eternally lagged Eden?