The reason is simple, the same month of it's launch EA also released battlefield 1 and pushed it extremely to take advantage of the recent pr disaster of: Call of Duty Infinite warfare; the game with 3.9 million dislikes on it's trailer.
It's a shame really, and since Apex is doing so well, we're not going to see a Titanfall 3 for like 9 years.
The only way to save the game is to just make the multiplayer f2p and release some content (which would probably be just recycled content from the first game). >>5732
To be fair on them, the games they made were cod 1, 2, 4, and mw2. Other than the last one I mentioned, there fairly fine games, most of the annoyance of cod was because of activision.