Isn’t ’wealthy’ usually defined as those with (or who appear to have) more than the speaker, much as alcoholics are those who drink more, etc? It’s always going to be relative.
There is also the theory that people identify with particular groups, even when it is blatantly obvious that they don’t belong and would never be accepted, and vote in line with that identification. I can’t remember the detail, but that is the explanation often given for working and lower middle class Tories. They believe that one day they could earn £X or live in the house on the hill, and vote accordingly, so that the interests of the group they aspire to are protected, ready for when they are able to join.
I think there’s something of a mixture of what has been said already. Self-preservation is a huge driver, which is understandable. If a party makes it clear that they will close mines, cut spending on universities or tax sweet food and you are a miner, an academic or work in a bakery you are unlikely to vote for them. You might argue that it is economically unsound to close mines that can never be reopened, that education is important to the economy and that people should have freedom of choice over what they eat. You might firmly believe those things, but the bottom line is that you are afraid that losing your job will threaten the security of your family, your home and lifestyle, and that is a very powerful motivation.
I suppose that for most people their political views are shaped by their own circumstances - they grow around our experiences - so a politician or political party/company who can tap into hopes and fears can present it as concern for the environment or as a way to move jobs from one sector to another, but people will vote for what will affect them, if they can work out what that is.
I think that explains a lot of the vague language used by all politicians these days. Talking about things being on their knees, off a cliff or under a bus is waffle, designed to hide the impact of policies on individuals. When the ‘debate’ is couched in those terms nobody knows what anyone else is talking about, anything can be denied and what seem to be promises broken with nobody any the wiser.
Some will find more altruistic reasons to explain their votes, but turkeys don’t vote for Christmas- and why would they?