I really don't think the issue was with "creating x from scratch", but from the purpose it was built for.
Game engines like Unity are general-purpose engines, they are not made for a specific type of game, and can be used for basically anything. The trade-off is flexibility and performance.
What they tried to do was to basically create a "clone" of Unity, that is, they tried to create a general purpose engine, and that does not make any sense at all for an indie developer.
If you're going to create a game engine + editor, then do it for a specific genre of games (e.g. FPS), and do it only if you're planning to create a series of games that belong to that genre only.
Unless you want to create a business out of selling game engines, then have a specific game in mind before creating a game engine, and tweak it for that purpose only.
Game engines like Unity are general-purpose engines, they are not made for a specific type of game, and can be used for basically anything. The trade-off is flexibility and performance.
What they tried to do was to basically create a "clone" of Unity, that is, they tried to create a general purpose engine, and that does not make any sense at all for an indie developer.
If you're going to create a game engine + editor, then do it for a specific genre of games (e.g. FPS), and do it only if you're planning to create a series of games that belong to that genre only.
Unless you want to create a business out of selling game engines, then have a specific game in mind before creating a game engine, and tweak it for that purpose only.