What a good memories! My first flight sim was Flight Simulator 4. Then came Chuck Yeagers Air Combat, Fleet Defender, LHX, Aces of the Pacific, and a lot more...
I realize that then were a sim for each era and scenario, they were more specific (WW1, WW2 Pacific, WW2 Europe, Desert Storm, Cold War...)
Now we have "a few" sims, but their content is almost every aviation era.
Examples:
il-2 with CUP: From WW1 to Vietnam and some moder jets
Strike Fighters: Almost every conflict and scenario since WW2
FSX: All the world
Now we have a lot of content in a few sims.
Then we had a lot of sims with less content.