As the Battlefield forum feedback at the time made clear, that is simply not the case. And 80%+ of the people who stopped playing Bf1 after its release (especially the console players) probably couldn't tell the difference between DICE and community servers.
Also, saying that people left because of a lack of custom servers is saying that Bf1's core gameplay sucks so badly that the menu is more interesting than the gameplay. In the end, you're affirming what I said, which is that Bf1 did not impress and was not well received by the Battlefield audience, and so did not hold people's interest.
While good custom server options are important to have, just because people were playing on custom servers in Bf4 doesn't mean that's why they were playing. Due to too many large concessions and constrictions to its design, Bf1 simply didn't deliver on its promise to return to Battlefield's roots, and didn't provide nearly as detailed an experience as the game people had just been playing, which was Bf4. In fact, Bf1 is the shallowest experience ever offered in the main Battlefield series.
I didn't find Bf1 a dull game to play because of its server menu (though I really didn't like its server browser and limited options available, either). I found it a dull game to play because everything in it was maximum reduced to the point that it wasn't stimulating and engaging at a level that would be just average for the series, and it wasn't worth my time when I could play other things, including Bf4 - which, for the last few years, has had more people still playing it than Bf1.
