The Dungeons & Dragons game has given competitors two great chances to come up with systems that can grow to be significantly popular in their own right - in the days when TSR almost went bankrupt, and in the days of 4E.
That D&D came back in both instances speaks a lot to its strength as a game. It's not just due to its prominence in the hobby, it's also due to it being a enjoyable game with wide appeal.
Other games do have problems with that "wide appeal" business. And honestly, a lot of them never will.
In all fields, you have dominant properties. But because the TTRPG sphere is so small, there isn't really that much room for smaller properties - certainly not in the numbers that get released.
(It's notable that during the 4E period, the most successful alternative was... D&D. That is, in its Pathfinder form).
That D&D came back in both instances speaks a lot to its strength as a game. It's not just due to its prominence in the hobby, it's also due to it being a enjoyable game with wide appeal.
Other games do have problems with that "wide appeal" business. And honestly, a lot of them never will.
In all fields, you have dominant properties. But because the TTRPG sphere is so small, there isn't really that much room for smaller properties - certainly not in the numbers that get released.
(It's notable that during the 4E period, the most successful alternative was... D&D. That is, in its Pathfinder form).