In my Last SP Dom1 game, I had a +1 luck, neutral order dominion. In my home province (Atlantis), I had a gold mine, silver mine, and ore mine discovered over the course of 8 turns. Combined with my +3 growth scale and the fact that Atlantis can patrol with Tritons (10GP fliers) this got me 899GP/turn there
Then I kept getting +100, +200, and +500 gold events in nearby provinces.
This doesn't really answer your question... but I know that in a previous games when I had luck and only my home province for quite a while, I kept getting good events in the home province. So I don't think there is any sort of limit. But I'm pretty sure that the number of events is not proportional to the number of provinces, at least above a certain level - in other words, having 60 provinces, in my experience, gives you about the same number of events as having 30 provinces, but having 2 provinces probably gives you twice as many as just having 1 province.
It sounds like your temporary absence of events was just due to luck.
-Cherry