is there a shortage of owners? old ones that may have passed away, or lack of new owners entering the industry, or even both? also are costs increasing regarding stalls, trainer's fees, feed, etc?
Depends on the jurisdiction. New York is costly. California has become geographically undesirable. Florida is seasonal and while weather is attractive much of the year, there is a falloff in the summer. Arkansas is hot and growing but mostly a winter/spring destination.
Available races as a whole are down from 20 years ago. Breeding is lagging due to costs. The glut of super trainers doesn't support the person whose means are lacking by comparison. Ultimately, bettors prefer larger field sizes yet that is a concern because the reduced breeding and the inevitable scratches cause frustration and displeasure. The involvement of HISA has supporters and detractors with legislation causing consternation in some corners.
Maryland will be reducing race days next year and while that stings, the lesser races there could boost field sizes in nearby places such as Virginia and maybe Delaware, New Jersey and Philly; mostly though at Colonial due to the turf course.
New York has become Chad Brown's playground, especially multiple horses in turf races and that can be a turnoff.
It isn't at crisis mode just yet but some ingenuity is needed. If places like California and even Texas eventually allow sports betting, maybe that enhances the sport depending on the language and if it relates to parimutual betting. The time of the C-virus oddly aides racing as it was a rare sport ongoing thus the betting numbers were exaggerated.