Honestly my interest and excitement for the project won't go anywhere if you need two or even three more years to complete it, so long as you get to make it the way you want it.
Releasing a game in episodes is always neat in theory, but in practice it can be become way more convoluted and time and energy consuming, especially if you originally envisioned a single story/game. You will end up needing double or even triple the amount of polish and bug checking because suddenly you have two or three releases, albeit each smaller in size. The worst feeling for a player is when there's a part 1 to a really promising project and a part 2 never comes out because part 1 took so much out of the developer, and wasn't quite a big of a success because a lot of people decided to wait for the "full thing". It can be really challenging.
I think ultimately it's your project and if you're confident you can split the story into episodes without destroying yourself, then sure. But if you can afford to keep working on a single game and release the full thing, even if it takes a few more years, everyone interested in the project will absolutely be more than willing to wait. There are so many games coming out, there's more than enough backlog to play.
I am in support of releasing a demo to give people an idea of how the game plays and how the tone is, and it will give you a taste of the kind of polish and extra work a "smaller chunk" of game will end up being.