Most games do indeed fail due to scope creep or lack of focus on the core features.
But I have also seen games fail due to lack of long term direction and vision. If you just keep building features without knowing what purpose these features serve in the grand scheme of things, you will end up with a meandering mess.
Some games just add a feature because it's what's expected of the genre without considering the wider impact on the systems. Like stamina systems in souls-likes or weapon durability in RPGs.
In my case I want to reconsider crafting and inventory systems because it's one of the things that has a few expected solutions that may not promote the type of game I have in mind.
I may need to do some concept arts to know where I am really headed.