They may show which way to go. With KS you propose the project not to the marketing etc., but rather directly to the customer.
Anyway I doubt that PF core was hindered in sales THAT significantly, because a lot of people who bought 5E core books have already their PF core on the shelves from the past. If there was a PF2 core release then it would have been different, but things that might have been touched are more likely the adventures and settings, that might just get purchased as an alternative to the Tiamat compaign for 5E, or not. That's the field where direct confrontation could be seen IMO.
I subscribe to the Pathfinder RPG line with occasional purchases of other Paizo products and a number on non-Paizo products. I bought all three 5E core books and the DMs screen (the books from Amazon, the screen at a B&N brick and mortar location). I don't buy Paizo adventures and won't buy WotCs either. Or 3PP adventures. I run my own game / adventures and I'm thinking of running both 3.x and 5E in my own setting. We'll see, there are things I like about both systems.
As for Kickstarter, I've been in on several (Traveller 5 and Bethorm). Neither of these came at the expense of another purchase or replaced another game. I've always liked Traveller and I'd like to run it again some day. And I'm a sucker for everything Tekumel related. From my point of view KS doesn't matter to my RPG habit, it just provides nice little surprises occasionally. I probably have a larger budget for RPGs than a lot of younger gamers though. It would be nice if I had the time I used to devote to them. *sigh* Oh, waiting on Star Citizen, but that's another addiction entirely :)