Like said before, it is the way the game works.
Server works differently because you might DC and come back, so it can just keep running. Solo game, it stops everything.

Persistence (what we call all the data that must be stored to recall when you come back) is costly in terms of performance. You might think your “particular case” it is “bothering”, but imagine all the data required to store tons of information to “load” when you restart the game. Unless you want more “progressed games” to take 20 minutes to start, what data is stored to load when you start the game must be criteriously selected.