It was different… Number of MP players in the session was limted by the Upload Bandwidth of the Peer Host … unlike in MSFS where the MS servers with a very high bandwidth, are sending out data to all the planes in the session… typical as many as a 100-200
In FSX / P3D, it was a struggle to get much more than 10 players in a session. better now, that most have higher bandwidth that 15 year ago, but still a limitation.
FSX was very much a limited “your small Group” MP system, where as MSFS 2020 is an EVERYONE near you system.