MMOEXP WoW Forever Explained: Why Blizzard Is Rebuilding Classic WoW Without Raising the Level Cap
https://www.mmoexp.com/Wow-forever/Gold.html

Summary
WoW Forever is more than an upgraded Classic WoW server. Blizzard is building a new permanent version of Azeroth around the original level 1–60 journey, while adding new quests, dungeons, items, professions, class updates and long-term progression. The biggest difference is that the level cap will stay at 60, allowing Blizzard to expand the world horizontally instead of replacing old content with every major update.