>It's not that newcomers have little chance, but more the symptom showing that there's little interest for competitive AoE2 play among newcomers

This isn't true. Hera & Lierey are two of the best AoE2 players and are both young.

There's an S-Tier tournament happening this week for anyone interested: https://liquipedia.net/ageofempires/King_of_the_Desert/5