You’re preaching to the choir WRT the extravagant public buildings. If I were “Dictator of the Universe” all public buildings would be very functional, not ornate. Of course, if that were the case, there’d be critics who would complain that the simple building styles would be “lowering their housing prices.”
FWIW, it’s not firefighters or their unions who ask for these stations (most would agree that it’s wasteful). It’s the politicians who often push for these things — the ones who get to put their names on the stations and who have their faces plastered all over the media during the “opening ceremonies” and the hoopla that goes along with it.
As far as the locations are concerned, these sites are usually owned by the cities already. They often cost the city less than if they were to go out and find/buy a new site. That doesn’t account for the money they’d make if they sell the lots, but the act of finding a new site, going through all the bureaucratic hoops to get it signed off for a public building, etc. will often end up costing more time and/or money than they need to spend.
Also, they have specific requirements for where they site these buildings WRT new developments, and have to be within certain areas, so they might be selling a cheaper (for them) lot to buy a more expensive one nearby at today’s price.