Tbh 2 years to create a demo isn't exactly much progress. I coded a full 45-minute game at 14 in visual basic within a month and that was during the school year.
Eh, the amount of time it takes to create a game depends significantly on the game and its level of ambition.
Cuphead took 7 years. Breath of the Wild took about five or six years. And numerous games took more than 10 years.
Some much more in fact. Like this one which apparently spent 13 years in development:
Duke Nukem Forever took about 14 years. At least one Doom mod started development before Duke Nukem Forever, and (as far as I can tell), is still in development years later. Will Star Citizen or Dwarf Fortress ever get finished?
Plus, as @WwwWario says, if you've got less time to work on something, it takes forever. I'm 100% guilty of that one... both my current projects have taken way longer than they should have simply due to me having no interest to work every day after 8 hours of work and 2 hours commuting.