Team owners make money two ways. What they win by on-track performance, but most importantly by what they are paid by the advertisers.
It is way down.
NASCAR has run off 2 of every 3 viewers it once had in slightly over a decade. If you are McDonald's or FedEX or Coca-Cola, well there you go.
And, again, this all comes back to the expiration of the TV contract after 24. IMHO, NASCAR will end up not only getting far less $$, but will end up on maze of complex off-beat channels and streaming services. How much is a main advertiser willing to pay for a race only a couple of hundred thousand will see behind an internet paywall? Why not buy 1000 more billboards along I-40 or 1000 more minutes of radio jingles?
Most observers believe that in the future teams will have shops that have only a few employees. Already, next year, NASCAR is switching from the current car to yet another "next gen" car. While NASCAR cars, since they stopped really being "stock" in the mid 60s, have been hand built by the teams, these are spec-mobiles that will be made in a factory in NC and sold to the teams. The "fabrication" part of the race teams have already been shut down and the people mostly fired.
It is going to get a lot worse.