When Rainbow Six Siege had first released that is would only have multiplayer only it made me nervous. Now PC has nothing to worry about because the longevity of PC, in general, has always lasted, but I have a had a horrible experience with multiplayer only games on consoles. That experience being soon as I am starting to get a grip on how to play they close the servers or the player count drops significantly.
This is not a scary practice if done properly, but how is it supposed to be done. The reason games like Overwatch and Rainbow Six continue to thrive is because they have a well-established multiplayer community. The difference between these two games is Rainbow was already an established series. Overwatch continues to hold its own because Blizzard genuinely cared about the community and they have the experience. Games that have failed were Battleborn and Evolve.
Battleborn is disappointing because since its initial release to compete against Overwatch, which was a mistake in own, there has not been much said about the game. As a matter of fact, I think the player count of Battle Born is extremely low currently.
Evolve came out a few years ago and the mistakes it made was that it was not a good game. The concept is cool but for a multiplayer only title the concept of playing cat and mouse all day is not fun even if you get to play as a giant monster. The game managed to revive itself by becoming free to play on PC but there are rumors that the player count has dropped and the servers are getting shut down.
So are console players ready for multiplayer only games? Yes, because if a game is good and gets the advertising it deserves it will live a long life on the consoles. There is a constant fear of being outshined by others and losing players. It is more referring to Battleborn than Evolve, because one actually is a decent multiplayer game. Also there many games that have multiplayer and have had only multiplayer in the indie market and were eventually shut down because of a low player count. Continuing on, it will be fine for multiplayer only games. Also with crossplay becoming wanted more by players it will double the life of multiplayer only games. So no worries.