Doesn't bother me. The purpose of Instagram for me is to look at my social circle's lives. If everything they do makes them less of a generic public social network Tik-Tok / Reddit / Facebook / Twitter style, I'd prefer that actually.
You're seeing step 1 and not realizing that step 4 or 5 is the entire web gated behind walls.
If you don't care, then you don't care. But saying there's no slippery slope? It's capitalism. It's happened with internet providers, it's happened with search engines, it's happened with social media, online stores, it's been funneling into a handful of companies for over a decade now. People want things for free and companies are willing to sell your data to finance their payroll. Saying it won't happen anymore is just naive.
The structure of the Internet precludes universal locking away. I am confident in my ability and that of my fellow engineers to always have alternatives.