The FGC didn't take Melee seriously, over the 14 years of its existence and plenty of time on main stage.
What makes you think that Melee getting main stage this year will change anything?
In my observations, Sm4sh shares more sensibilities with FGC games. The neutral game, footsies, transitions, mind-games, etc. are very reminiscent of SF4.
Melee is more comparable to SF3, which had been easily phased out by SF4, which will be phased out by SF5. (The natural progression of fighting game communities) Meanwhile Melee has been kicking and screaming in defiance to the advancement of time, tech, and subsequent entries)
If the FGC will acknowledge any Smash, it's more likely going to be Sm4sh. The tendency to hold on to a 14 great old entry with childish, bitterness towards Sakurai and the new titles, selfishly wanting a Melee style Smash when that clearly won't happen again, is one reason why the FGC won't take Smash seriously, and views us Smash players as immature children.
Is logical for EVO to NOT push Sm4sh to the back burner. It would please Nintendo (sponsor and all), it would help Sm4sh grow (being the newer game while Melee is so old and established that it doesn't need any more biased publicity), and would solidify the Sm4sh ruleset worldwide.
In the long run, there are more benefits to Smash, as a franchise, to help Sm4sh along by giving it the spotlight this year and seeing how it does. Especially since Melee lacks the accessibility to bring in half as many new players as Sm4sh does. Players who will become fans of the franchise, ensuring that the Smash franchise will keep going.
This is coming from logic and business seems, not bias.
Sorry man but there are TONS of inconsistencies in your post. Lets first talk about your comparisons to Street Fighter. First, you say Smash 4 is more like Street Fighter 4 than Melee because "neutral game, footsies, transitions, mind games". I'm sorry, but what are you even rambling about? Smash 4 does not have a more interesting or varied neutral game than Melee. In Melee, you have more safe options in neutral than you do in Smash 4. You can do more things. In Street Fighter IV, you have more options. In Smash 4, you are actually pretty severely limited on what you can or can't do in the neutral game. For some characters they literally have an amount of moves that you can count on one hand that are fit for playing footsies with. Smash 4 is
nothing like other fighting games in this regard.
Second, you say Melee is more like Street Fighter 3. I also think that this isn't necessarily correct. First of all, it depends on what version of SF3 (or SF4 for that matter) that you're talking about, but I'm going to go ahead and assume you mean Third Strike. Third Strike is a more precise game in general than Street Fighter IV, and it supports somewhat more aggressive play in the parry system, in that you can be aggressive in your defense. But Street Fighter IV has an abundance of more frame tight links than Third Strike, and some matchups are even more punishing than common matchups in Third Strike were. Melee is no more similar to one than the other, in fact, Melee is a lot more comparable to games like Blazblue, where the goal is to try to get your opponent stuck on the defensive, and in the corner, where you can exploit them with long block strings and whittle down their defenses and convert into long combos from it.
I promise you, Smash 4 is no more relatable than Melee to most other fighting game fanbases. In fact, it's highly arguable that it's even
less so because there isn't nearly as much execution skill needed, which is itself a somewhat contentious part of fighting games in general, with the majority supporting input skill being a major facet of the game. At the very bare minimum, people who play games like BB, UNIEL, Street Fighter, etc can respect the precision and input speed needed in a game like Melee. It's harder to appreciate it in Smash 4 because the precision comes more from timing and not necessarily speed for the most part.
Also, lol, Smash 4 being at Evo has
nothing to do with the Super Smash Bros. franchise's ability to continue. Smash Bros has existed without tournament support well over a decade. It is established.
EDIT: Also, SFIV has NOT replaced SF3. There are still Third Strike tournaments. There are still SF2 Turbo tournaments. It was on the main stage at Evo last year. You don't know much about these communities.