You'll see in the article that Kickstarter or crowdfunding would not have validated this idea, as the difference between backing / pre-ordering / investing in a product versus purchasing a product is significant. To validate an idea, you need to know that you can actually sell it in a repeatable fashion. Kickstarter or crowdfunding is generally a once-off process, so doesn't give you that validation.
(I know that many Kickstarter projects that were successful have turned into longer-term, sustainable businesses.)
We don't have any data, but "would not have validated the idea" is ... perhaps not 100% accurate?
People do manage to "kinda/sorta" validate their ideas by getting email signups. Granted, it's less accurate than actually collecting CC details, but it does provide some indication. And kickstarter involves actual money, so perhaps it gives you a better idea than email, even if it's not quite as good as getting their CC. Maybe that tradeoff is worth it in terms of openness with your future customers?
(I know that many Kickstarter projects that were successful have turned into longer-term, sustainable businesses.)