While there have been a surge in young bodybuilders and strength athletes blowing up pretty quick then disappearing just as quickly, it's nothing too new. Three of my favorites when I was younger, Hayley McNeff, Jessica Work and Jess Williams (Queenstarfish on YouTube), went kind of the same way (but for Williams, I also think her father's health also contributed to her "retirement").
But you are right in that social media is more than likely fueling this. When algorithms reward those who have the most extreme physiques with high engagement, it not only pressures those who have that to continue to get bigger, leaner and stronger, but also those who compare themselves to those influencers to aggressively and quickly do what they can in order to look like that. Unfortunately, when you're young, it's much easier to not look into the long-term consequences of heavy drug use.
We'll still see bodybuilders and strength athletes last 5+ years, but they will be those who train with longevity in mind and don't blow up super quickly. The ones who explode in a relatively short amount of time? Don't be surprised if they don't stick around.
There have been discussions on the Forums here for 10+ years about how Physique has replaced female bodybuilding. Some of the wellness competitors of today, that I've seen, resemble FBBs from 30 years ago.
Bikini competitors today are as big if not bigger than bodybuilders from the 1980s. A lady I knew used to compete in the early-mid 1980s here in Australia and once told me her gran-daughter was bigger and using more stuff for bikini than she was when she competed.
I don't know some fbbs stay active for a long time. there are some older fbbs who have been muscular since the 90s or late 80s and stay muscular for most of their lives. others quit for decades only to come back at age 50 + stronger than ever. but with how hard this stuff is many will quit at some point for many reasons. I think it's about routines it's hard at first. then they get used to it but then something happens that breaks the routine and it becomes a lot harder again leading to her quiting.
Anybody get a look at how some of the greats from just 5 years ago are gone? The massive amount of drugs take their toll and the women check out. Thankfully, they get out early enough and they don't put themselves into an early grave. Today's Ranya Dally is yesterday's Michaela.....is a prime example.
The lifestyle can be a factor too. I know a former Figure Champion who is remarried and has a lot of kids, turned to God and left it all behind. We talked a few months ago and said the amount of drugs pouring into the sport today coupled with the social media pressure probably would have turned her away. In her prime, her ex was also a bodybuilder and turned out gay or at best bi. Caught him cheating with a dude. Just an absolute nuts story. She said you take people with body image problems and pair them together and then they get the attention they are craving and the side drugs along with general creeps in the game and it is a meatgrinder of a life. All this from someone who put herself out there in the early FBB porn days. No active sex, just nude posing. There are regrets.
I don't think we'll ever see many past champions stay in longer than 5 years. No more Diana Dennis' or others who lasted so long.