To put this in the bluntest, crudest, most simplistic terms the availability bias is a trick of associative memory our brains play on us. If A happens in an unusually memorable way we are apt to think that it is likely to happen again even if the odds of this happening are remote. The availability bias is a good chunk of why people choose to get lottery tickets even though the actual odds of winning are so remote as to be ... well, I'll just refrain from stating that opinion as starkly as I could.
Appealing to the availability bias is the basis for a lot of sales pitches. Against all actual odds "you" turn out to be the lucky winner of some huge undisclosed amount of money from some foreign national who supposedly mentioned you. If you work from the supposition that this thing never happens in the real world at any meaningful level then the standard scam of selling you on your untold millions becomes harder for you to be taken in by. This doesn't mean you can't ever get conned, just that once you know how absurd the real odds are it's tougher to be taken in.
I would propose the availability heuristic is at the core of presenting certain things as innately plausible. For instance, I've met a few guys who may think that because some guy they thought was average-looking ended up marrying a widely renowned beautiful woman in the community that this should happen for them, too. I'm not going to say where I saw this happen a bit because regular readers don't need to wonder where. I saw this a bit.
I heard it a bit, particularly after a couple of attractive friends of mine got married. There were some guys who didn't think through that a ten to thirteen year age gap between themselves and the woman they thought they had "something there" with was not prima facie evidence that something was gonna happen. Then there was the lack of likelihood of pairing due to divergent interests and values. But the availability bias, arguably, had kicked in within the brains of these men. They saw that so-and-so married so-and-so and the first so-and-so was deemed "average" in looks, therefore ... . The first so-and-so is a funny, loyal, and interesting guy. The other so-and-so's who deemed the guy average were simply considering themselves to be at least or more worthy than the married so-and-so of getting the hot woman.
For the guys who think the situation is just a matter of finding a woman they like enough to make a deal with they forget that this thing about the buyer's market is omnidirectional. Years ago I was conversing with a guy who, as I've mentioned before, declared that he thought it was sinful to consider any woman out of his league. He seemed to be thinking in terms of an availability bias. There was never any question what he had to provide a woman that would be an incentive for her to be with him; the guy's mind was on the subject of settling on which attractive lady he would bestow his attentions and interest.
Honestly I can't feel bad for the guy in his unwavering bachelorhood. When he saw a discussion about whether worldly definitions of beauty were informing how some Christians viewed beauty and attraction the guy told me that he noticed it was the less attractive women who got up in arms about that sort of thing. When a guy talks like this it makes it impossible for me to take him seriously as someone who will end his run as a bachelor by getting a girlfriend or a wife. Should we flip things around and say that it only tends to be the unattractive and shallow men who complain about the shallowness with which women obsess about things that are supposed to be shallow? But I digress. The availability bias may well be what permits any person in the dating scene to have hopes that are tantamount to winning the lottery.
I also suggest that the availability bias would be at the heart of anyone who would actually believe that if X gives Y to organization Z that X will necessarily keep his/her job having givin Y to Z. If Z sells this as a possibility then X is even more likely to believe it but this does not make the outcome more likely. If Z proposes that A gave B to Z a few years ago and now A has a great job this is omitting the rest of the aphabet who may or may not have been knowingly involved in the process who don't have jobs or access to the benefits of B once A gave it to Z. To borrow a line from Phoenix Preacher here is where you can make your own application.