Figured I should say this while my platform is still (kind of) small:
You CAN be professionally successful as an artist *without* a large social media following!

Sometimes a large audience is needed, e.g. if you want to make a living from private commissions or merch sales.

But that's just one way to do it. There are others.
Traditional mainstream avenues for illustration work have been there long before social media, and continue to exist. 
How did illustrators find work in the 90s? Yes, a lot of that is still valid.

For example, I got my first jobs in book illustration, and did my first graphic novel, by pitching directly to publishers.
These publications are what caught the attention of more clients.
My website, illustrators' org membership portfolio, & word-of-mouth also helped a lot.

Social media? Not so much. 99% of inquiries I get in DMs aren't interesting from the viewpoint of someone who needs to make a living ("can you illustrate my childrens' book, my budget is $50")

So don't sweat follower numbers, at least not yet. Focus on reaching clients first!

If your work is solid, and you keep posting and showing it in many places and to targeted potential clients, the right clients will eventually notice, even if no large audience does.
The vast majority isn't going to care about your follower numbers (at least not yet).

This is based on my experience illustrating freelance for 8 years now (13 if we also count part-time).

Of course I'm worried that in the future, clients might care more about our follower numbers, because I keep hearing about that, but that's another topic for another thread ...