People don't Google-search them?
Bad/no SEO or similar?
"Facebook-Only" ads? Is there no other "as effective" ad platform or method? Is there some sort of cult mentality around Facebook ads [and/or ads on other platforms]?
People in 2021 just don't think "Gee, I wonder if that place has a website"? My local nobody "mom & pop" drycleaner seamstress has a website, or at least is Internet-searchable.
Google search takes me to business' Facebook pages all the time.
I don't have a Facebook account, but end up there pretty often because lots of small businesses only have a web presence on Facebook. Google finds them just fine. IIRC some even set their Google Maps website link to their Facebook page.
I hate social media generally, but it'd be hard to argue that your average small business, craft seller, et c., shouldn't prioritize a Facebook page over a "real" website.