I like to think about, how would you find a doctor if you needed one? Would you ask your PCP? Would you google "X near X town"? Would you look at your insurances website and see who was in network near you? Would you be discharged from an IOP and given a list of local practices to schedule with or be on the list that the social worker contacts to set up aftercare? Especially if you have no presence at all in the area initially, you have to make sure you're hitting all the avenues for people to know you even exist. I can really want to buy a BMW and the new BMW dealership that just opened up might really want to sell me one but unless we cross paths, I'll never end up buying that product I wanted.
People make this mistake of thinking that just because they setup a practice and get in network with a couple insurances, patients are going to start flocking to them but unless you're part of big healthcare system, you aren't going to get a lot of automatic referrals your way.
I could certainly see new all virtual practices being extremely slow to fill. You're competing with literally every other virtual competitor nationwide. Having in person availability to at least some extent keeps your competition more local unless you already have an established presence and referral pattern.