When the developer allows Kickstarter backers to access alpha at much lower prices (~$25 tiers) it all transitions over to SEA with much less sticker shock. Of course, alpha access tiers tend to be the more popular ones, so developers seem to struggle to find a balance that will make the the funding they're looking for without causing a ton of backlash once they show up on Steam.
I honestly think that asking people to PAY for beta/alpha testing access is one of the core things wrong with today's games market. No one should pay to test a game, they should receive something for the effort they are willing to put into it. The more valid information (new bugs found) they submit the more they should get in return imho.
But yes this is exactly the point where KS's struggle, I think the best example of that was Planetary Annihilation. They completely ruined themselves and any credibility they have. Due to the high price of the KS they ended up having to ask 80$+ for early access and are now still at 45$ which is AAA price point. There is allot of vitriol going around with this game. For me this is the perfect example of how not to manage your KS/SEA.