As someone who's admittedly never really been into NASCAR, why can't NASCAR actually make the "S" stand for something again? Returning to the whole "race on Sunday, sell on Monday" thing sounds like a win for almost everyone - it makes it far more affordable for teams, plus it would make the cars profoundly more diverse than just having a tube-frame chassis with a shell over it. Do you think people are going to buy a Mustang or a GR Supra because they saw it in NASCAR, the way that these racers have next to nothing to do with the production models?
The cars haven't really had anything stock about them since the 1980s when they fully switched to those manufactured sheet metal bodies on a tube frame chassis, and the auto industry rendered "win on Sunday, sell on Monday" obsolete at least two decades ago. The closest you'd get today is "Win on Sunday, get declined for a lease agreement on Monday".
I've also been very much disinterested in the whole "turn left" phenomenon. Why not go all over the country (and maybe a bit beyond it, like in Canada or Mexico) and race at either non-ovals or infield courses, like those at Daytona and Indy? Is it really surprising that NASCAR seems to always be in trouble in terms of finance and viewership when most races are just the same three or four turns for hours?
The financial trouble is a long term effect of rampant over-expansion after the "golden era" of the '90s, when people were literally fighting each other for tickets to go watch cars go in left hand circles for hours. Even after that era started cooling off they just kept building more tracks and diluting the market with less interesting races. Eventually the national economy started downturning, so pricy luxuries like tickets to racing events and weekend trips to stay in price-gouging hotels were out of the question for the more casual of its core demographic. Then the more hardcore fans started leaving as their favorite '90s era drivers started retiring, and eventually even major places like Bristol went from selling out three years in advance to knocking down grandstands that it couldn't hope to fill anymore.
Though it's not unique to NASCAR, motorsports as a whole is struggling with the same issues since slapping a company's name on any old car in the field just isn't effective advertising anymore. Nowadays they only want to sponsor a driver who's guaranteed to get lots of TV time, not the team they're driving for at this moment, and if the teams aren't getting steady revenue then the quality of the racing suffers as a result, which drops the viewership, and the spiral continues.
Heck, maybe they could even borrow from Super GT500, if they're so set on not using anything resembling "stock" vehicles. I'd say even those cars look more like their road-going counterparts than NASCAR machines.
I'm still of the belief that the "Car of Tomorrow" of the late 2000's was less an attempt at better aero and more a half-handed attempt at copying the look of European touring cars since they found out that people could watch other non-NASCAR things on the Internet. It was terrible and no one liked it, so I doubt they'd try it again even if they did figure out a way to make it aerodynamically superior.
I want to respect NASCAR, but it feels so hard to do that sometimes. It's especially frustrating when you mention racing to someone, and the first thing most people think of is NASCAR and not like, IMSA or something.
It's primarily due to cultural ingrainment thanks to celebrity-status drivers and a heavy layer of marketing in the boom times. Everyone knows NASCAR because it was on soda machines and billboards and pop culture references in TV shows all over the country, everything else just continued on in the background and was largely for "car people", not the general public.