I think you're just disorganized. I just sit one time a week to do 20 bosses. Start with Kanto and almost all Johto. Next week I finish Johto and do Hoenn and Sinnoh. Around 4 hours a week needed, not anymore. You're just blaming your disorganization on the game.
Don't have four hours a week in one sit? Then just sit one hour for four days. Same result.