Pro Stock has a choice to make, and I do believe time is running out (5 years tops) to make a decision on which way this category goes. Let's face it, Pro Stock has been around since the 60s/70s. It's an old product. If it is to survive, it needs to advance, but not price itself out of existence (already happening).
Car Manufacturers are refining their offer to the public each year (technology, functionality, fuel efficiency etc). Sponsors look at relevance, ROI, marketability, and a whole swag of other factors. Does the category go Turbo? Does it push for market relevance (EFI, foreign manufacturers) etc.
I see the appeal of Nostalgia racing, even Nostalgia Pro Stock - it's an affordable option in an increasingly expensive sport, and has a lot of emotion attached to it (a throwback to the good old days). It's a good 'ying' to the 'yang' of the Big Show.
NHRA prioritizes what sells in their market - Nitro. Take nitro out of the equation, and the spectator numbers at a National event are much, much lower. Blame the spectator. They like what they like.
In motorsport, dollars drive performance (unlike stick and ball sports, where the average joe needs very little equipment to get started). When the ROI is less than the cost of going racing, sponsors will ask 'what's the point?' This has been happening for years.