I have a collaborative agreement as well. Essentially, I have almost total autonomy, but I refer to/consult with my in-house physicians frequently.
For any APN to think that a practice without a collaborative agreement means to be totally "on your own" is inaccurate. No healthcare provider practices totally "on your own". It takes a close working relationship with the providers in all areas of medicine.
As for liability, yes, when you have a collaborative agreement with a physician, he/she will be liable for anything the APN does. That is true for any provider that takes on the responsibility of a patient either by consult or assignment acceptance.
I fear the push for no collaboration might offer the false sense of security that many APNs will "think" they are solo and therefore, no need for any input from physicians/other APNs. Unfortunately, there are those out there that resent the "stigma" collaboration carries.
I have zero issues with it. I'm not a physician nor do I hold myself out as one. But, I do, after many years experience, practice with almost complete autonomy.
And, a collaborative agreement does not reduce mistakes either.