One of his most famous paintings matches 2 out of 3 of your criticisms, he only went wild with colour later. I agree the style change can seem abrupt but it happened over years.
You'd think the sort of person that wanted to pay art thieves would be more interested in the prestige of a famous or characteristic work than a relatively obscure naturalistic study of a garden he painted several times. I mean, similarly, anyone interested in studying the history of art sees Picasso's naturalistic family portraits he made as a teenager and his 'blue period' as important in his development as an artist, but it's not the stuff I'd imagine is high on the list of wealthy criminals wishing to flaunt their wealth and power with famous abstract paintings worth millions in their private rooms.
Though I doubt Van Gogh's more famous works were on display at the Singer Laren museum...
If you put "Van Gogh painting" in Google images, you have to scroll quite a bit to find anything in a similar style, except for a couple hits from current news pieces.
https://en.m.wikipedia.org/wiki/The_Potato_Eaters