While marketability would increase, as society starts to think of the furry fandom in the same ways they do the anime and sci-fi fandoms, it also means an increase in the chances of furry sites accepting adverts from outside the fandom. And advertisers want to also reach a wider audience, possibly more children, so they would want to cut out any adult aspects where possible and focus on that. Not all adult parts of the fandom are sexual, many times we're creating comics and art that we enjoy, this would be a shift towards something a specific age group would enjoy.

Because the target is the mass market, it also means governments might want to step in more often and dictate their own politically inclined rules (which is fair, because at this point the fandom would be reaching a wider audience, meaning regulations are going to happen). By reaching a wider audience the fandom is open to more limitations on what can and cannot be done. This can be seen as a good thing, because gradually the adult image of the fandom would become impossible to bring back.

One issue though, is acceptance. When people join the fandom, it's done knowing that to a lot of people outside the fandom it's a little weird and strange or in their opinion bad for one reason or another. It weeds out anyone who isn't prepared to hide this part of their life from family and friends, or motivates them to dive into this as a kind of lifestyle choice that mostly pushes people who don't like it away. It's a little isolating, but the whole fandom's gone through this process, and much like hazing in the military it can create a kind of camaraderie through a universal shared experience. Without the adult aspects of the fandom keeping people out, this camaraderie will fade.

The reason this becomes a problem is without that camaraderie tying everyone together you get subgroups who start fighting each other. You can't just have a whole fandom where everyone gets along, you need to separate your in-group from the others. In anime there's groups for individual shows, in sci-fi there's always been fighting between star wars and star trek if only because it's fun to fight over nothing important. If that pisses you off, I've proven my point. The furry fandom does have internal groups bickering with each other over what counts as furry, there's memes over these arguments, but the furry fandom is a small enough niche that anything with furry art is considered good. For us, depicting Lola Bunny and Krystal next to each other would be normal fanart (usually adult fanart though). If the fandom became less adult, then you'd get more arguments, like the way the MLP fandom argued that they aren't part of the furry fandom for a decade after G4 came out. It's possible that the fandom would split as new shows with furry characters come out, but their fans don't feel they count as part of the furry fandom because they've tied their identity to just this one show.

I don't think this would kill off the fandom, the whole point of becoming more socially accepted is to reach a wider audience, but change definitely will happen whether we want it to or not. As members of the fandom grow in number and get older, we're also adding to the average opinion of the furry fandom, we have kids and have them watch the shows we loved, and so the fandom will naturally reach more people given time even if there wasn't an economic incentive to do so. But just remember that a wider reach means less personal identity and more brand identity. Be wary of how the furry fandom as a whole is being rebranded, but also don't bother trying to stop it, maybe just try to steer it away from the mistakes of the past.

Remember, cartoons used to be for adults in the west, the Hays Code and other events forced Betty Boop and other characters to tone it down, and their popularity waned as a result. Today we're starting to see a return of adult cartoons, not pornographic, just ones with deeper plots than cartoons meant for kids have, more blood and gore, something that pushes the boundaries we made up in order to reach a wider audience, families. Japanese animation didn't go through the same events, and so adult targeted animation has always been around, and western translators attempted to tone it down or remove the parts western society opposed, like making two sailor moon characters... siblings? or are they cousins? Whatever, in reality they were lesbian lovers as far as I recall, and you can't have that in 90s kids television.

The furry fandom has a natural buffer against this. It's the NSFW art and image of the fandom. People assume the furry fandom is a sex thing, and so we get to keep our complexity and adult targeted narratives, comics, shows, games, etc. Erotica sets the societal bar very low, and so the whole group is free to express themselves fully. If someday the NSFW side is somehow banned and pushed out, then the bar for what is acceptable rises, the target audience grows while the allowed content shrinks.

I mean, this doesn't hold true just for the furry fandom either. If the internet as a whole tries to improve its image beyond "the internet is for porn" then we're going to see more automated policing of the internet so that people across the world think it's safer for kids to use. What that usually means is "ideologically preserving", they don't want their kids growing up with the tools to look at all the nations of the world and take inspiration from the best parts of each, they want their kids to learn their parents values, have their parents religion, their parents education, their parents opinions. Can't do that if they've seen more than their parents ever have or will.