so this isn't so much a peeve as "Well -- things change." Back in the day they did auto, or at least tire, service at every gas station i.e. the 'Service Station.' Every 'service' type gas station had a commercial air compressor for their tooling. And every commercial sized air compressor does a pretty good job of dropping the water out of the air in the holding tank so you get fairly dry air into your tires.
The modern "convenience store with gas pumps" establishment likely does not have a commercial compressor - just some kind of gadget on a pole with no holding tank, so you get wet air into your tires. After a number of years of being filled with wet air, alloy wheels develop enough surface roughness under the bead that they will begin to seep air. PITA.
You can buy a home compressor with a small tank, but tank compressors small enough to be portable, while better than tankless sources, don't do that good a job of dropping water either...