Also what do you thin happened to the people who grew up solely on hiphop? do you think they retired from listening to rap once they hit 30?
These people still exist and they still buy music & they still go to shows.
Our disconnect seems to come from you thinking that the hiphop demographic only extends from 18-25 or something. This is a new era and in order to be a star in hiphop nowadays you have to be able to reach both the 25 & under & the 25+ hence that list of rappers i put up there who make music that can relate to both and hence are getting full support from people who consume their music solely off streaming/social media & those who still receive music through radio/video platforms.
Also about your point of "little Gilbert in Bubble ****, Wisconsin who needs the TRL top 5 to tell him what's popping and all the new slang..." he still exist in large numbers actually, however he doesn't take as long to catch on because TRL has now been replaced by Complex, The Fader & grown up Gilbert who is now a "tastemaker" drinking artisinal water in a small BK shack, writing articles promoting 21 as the new 2pac.
You are thinking under the scope of someone who isn't taking into account how many people don't pay big mind to social media or the club. I til this day have never heard someone talk about tech nine in real life, nor do i see his name come across my TL more than once every quarter year....He is doing bigger shows & selling more tahn most artist who people claim to be hot right now.
you mentioned Yachty having a sprite deal... well on the other end of the spectrum Rakim is in a nationwide televised add for sprite right now. Why? because hiphop isn't solely reliant on the youth anymore.
For the past two years the internet told me thug is hotter than wayne, Ask any promoter world wide if they could book both for the same price who they're gonna end up picking

.
For years older rappers have been making music specifically for their core fans, droppin projects & touring the world off of them & i sat here and watched ya'll call the artist irrelevant...... now young artist use the same model and you can be one of the hottest in rap w/o getting radio play & doing 20 city tours..... MY how the narrative has changed