Comment: Base rate fallacy (Score 5, Informative) 998
It seems good to read http://en.wikipedia.org/wiki/Base_rate_fallacy (or other articles on the topic). If the article is correct that 2.4% of new cars sold are hybrids (which sounds reasonable) then the base rate expectation for a "random person" buying a hybrid is low. If the probability of a previous owner of a hybrid buying one next time is 35%, that's still around 14 times the base rate expectation.
Now clearly, car buying habits are hardly monte carlo style distributions. There is a considerably greater "loyalty" to specific cars than just the random assignment of an available vehicle to a driver. Most of that is probably pretty closely tied with income and socio-economic status. Also, obviously occupational effects matter; and also regional ones do. But consistency in brand or style in repeated car purchases is most certainly far lower than 100%.
It is not at all clear from the evidence given whether hybrid-loyalty is greater or less than other types. For example, I *just* bought a Honda Insight (which seems a lot less common than Toyota Prius, despite what seem to be even more favorable reviews; name recognition does seem big here). Like literally days ago, so I'm probably not good evidence in any direction about next vehicle purchase. But prior to that (and still), my partner and I own an Audi A4--a brand that probably sells no more than 2.4% of cars in the US (i.e. the brand as a whole, not the specific model which must be lower still). Even if a hybrid were out of consideration and I could only consider a conventional gasoline engine, I think there's much less than 35% chance I'd choose an Audi for my next car. Not because I have any particular criticism of Audi, but just because there are lots of other choices, even given similar driving patterns and socio-economic status. I could buy a Saab, or Volvo, or Acura, or maybe on a bit pricier side a BMW, Mercedes, Lexis, or slightly downscale a Buick or Lincoln, or a VW which comes from the same factory even. All of these are pretty comparable, and brand loyalty might lean my decision slightly, but there's a long way to go between the base rate--even of only "semi-luxury sedans"--to get to 35% brand retention.