Will it live up to it? It'll probably be better and obviously more inclusive.
Objectively, it took 10 years and 20 movies to setup Infinity War and End Game. That's a lot of time spent putting granular pieces into place and readjusting as they go. Learning from mistakes.
Also, sure everyone loves the big 3 now... but let's not forget that RDJ's Tony Stark was the only one the general public rocked with out the gate. Thor 1 was one of the worst reviewed movies and nobody even bothered watching First Avenger, it made the least amount of money of any MCU film. Back then Cap was corny and Thor was a lame.
However, look at the amount of work (and rework) they put in to change the perception of both Cap and Thor. Hell, it took them 3 movies and a youtube skit about Thor getting a roommate before they let Hemsworth be who he is and not who he's supposed to be.
Black Panther, Captain Marvel, even Dr. Strange are already in better shape out the gate than the original big 3 were back in 2008. And we've only seen the early build of those characters, not the final form like we've had with Tony, Steve, and Thor, after 9 solo movies and 2 avenger films to flesh them out and iron out the kinks.