The Model-3 will be purchased by a whole different breed of consumers. Ones that are not early adopters or fanatical about this sort of thing. I predict that the majority of Model-3 consumers won't be huddled around a forum, drooling for scraps of information to feed on.
I agree Model 3 will attract a more mainstream audience and one that is, on average, less enthusiastic and thus less likely to frequent forums like this one.
That said, my gut questions your conclusion. My own experience from for example the world of Volkswagen Group forums, suggests that while the likes of high-end Audi and Porsche may attract more passionate owners by nature, the sheer volume of Volkswagen and Skoda owners will eventually dwarf those.
It is simply a numbers game. Even if only 1 in 10 out of 100,000 people gets involved, it is more than 1 in 3 out of 10,000, just to throw some numbers in the air for illustrative purposes.
Now, I agree this may not be the case in pre-release spying. I expect the Model 3 attendance figure to seriously go up only once it is available. But already today, I think we can see enough of "waiting for Model 3" people frequenting even the Model S and Model X forums to make at least myself take note.
The flood will eventually overrun this early adopter sanctuary too. And that's a good thing for TMC, Tesla, the mission and for all of us.