It's simply not possible without a large well funded team.
I really don’t understand this. All my current browsers don’t need more features. They didnt 5 years ago either.
There are security updates, for one.
Plus there are a bunch of CSS improvements and the like in the last five years. If you don’t keep up with the competition your users are going to see broken sites eventually.
Wow, that’s... something. Keeping a browser engine of that size maintained independently is going to be quite a task.