My parents have a guava and sour orange tree that grow along a very busy street in southern california.
The oranges look delicious, but are sour as hell. They are mostly used for marinades. I feel bad for the people that have been burnt on them.
The guavas are fantastic, but almost nobody in socal knows what a guava looks like. Once in a while someone will recognize the guava tree and gorge themselves. Considering good fresh guava is not only hard to come by, but around $8/lb if you can find it.
Side note: I was born and spent a lot of time growing up in Brazil and like Guaraná in soda/soft drink form (Antarctica brand). I didn't think I'd find it when I moved here, but this store had four pallets of the stuff on display on one of my first visits.
Probably more of a regional thing. Lots of Guava is grown and sold in Florida because of the demand. I suppose that makes it easy to get up the east coast at a lower cost.
Guava doesnt grow well on west coast (at least on the commercial scale) and there is much less demand, so that's why prices are so high.
When harvest time comes, we pick what we need and want to use or process, then advertise to the neighborhood that they are welcome to come and pick.
Often, no one wants to invest more labor than to pick up a box off the porch.