How many Arabians are racing in the USA?
As far as I know there are no full card Arabian races carded at any track. Delaware has had a few in the past and Los Al used to have them, plus the CA Fairs. I think the last race on either Big Cap day or SA Derby Day at SA has a stakes race.
No supply, no racing fans or betting.
Here is the race schedule for 2018 for Arabian racing in the USA
https://34z5as1d9gu01m1geu13gzkc-wpe...etcalendar.pdf