Your Previous Lead Developer is the Dungeon Master
medium.com
medium.com
Experience counts for little - the new generation will solve the problem in a 'better' way.
Sure, things have changed and 'best practices' are constantly evolving, but it's a very dangerous path to see 'new ideas' as being better than experience.
Software does not escape the tragedy of history repeating itself.
I'm struck though that the DM would necessarily have to have the big enough ego to consciously or unconsciously block new efforts. Like the post says let it go. And if they let it go, where's the positive case for that?