There's a slight difference. You're FUNDING development, which normally means you would be looking for a return on investment once the product is ready - but in this case, you are getting some agreed upon rewards instead of a share of the profit from sales. The problem is that development isn't always smooth and linear, and that's even more true the smaller your team is - being sick for a week during a given month means that the output of a single person team is down 25% from baseline. Tack on a couple of other challenges, and it's easy to see how updates slip completely, or contain way less content than anyone wants. Not to mention that unless your patreon bucks are substantially higher than your monthly expenses, you either have to have a backup fund to cover attrition of funding, a second job, or regularly do a bunch of promotion to bring new funding in. And if your issue is that it turns out to be harder than you thought it would be to make as much content as your audience wants every month, then you need to figure out whether adding someone else to the team (or farming out some aspect on contract) is worth the additional tax of communicating, meeting, documenting and all of the other stuff that you have to do when you collaborate.
Just saying - this ain't an easy thing to do well, and the audience isn't very forgiving - unless you're making a furry game - the furries will forgive any amount of delay, sandbagging and grift if they think you're going to make something they'll like.