Can't say for sure. The class/level/spell-progression tables sure went past 10th... and 20th, for that matter.... 2e seemed to cap at 20, not 10, but didn't appreciably change anything that might've made higher levels work better.
But, 3e they prettymuch admitted they didn't bother much with playtesting or anything beyond level 10, because, 'people don't play high level' (yeah, because the game doesn't work at high level - sure, because it doesn't need to because people don't...). And, of course, E6 was a popular variant that lopped off higher level issues.
In spite of that, the MI in BECMI went to very high levels, 3e had PrCs with high preqs that became available at high level, and the Epic Level Handbook (whatever one may have thought of it), and 4e, it's tight balance holding up to high level play, replaced those with Paragon Paths at double-digit levels, and added Epic Destinies beyond 20th.
And, 5e the exp progression vs the encounter guidelines reveals a game that's designed to level faster (not take as long to get through) at levels 1-4 and 12+, recognizing the 'sweetspot' where people actually play (ie the game sucks less), between 4 and 12.
Yet, the heavy use of dragons and the themes of Dragonlance seem to cry out for high level play. No? And, it also seems to have setting-specific organizations, (moon) magic, and the like that, in 5e, would usually be baked into some sub-class, starting at low level...
Could be an opportunity to add back Prestige Classes.