> Beth Israel have every single day and time slot (90 days worth) booked for all their Neurologists until March? Yeah okay seems legitimate.

They don't, they have plenty of open slots even this week but they will fill up with more urgent cases. When your referral comes in they will make an assessment and schedule you accordingly. When I had a PPO plan, I tried to see a specialist for something urgent but was quoted 3 months. It was something urgent care couldn't deal with but it wasn't life threatening so ER wasn't appropriate either. I got a referral and was seen the next week.

PCPs also have plenty of availability. I can get an appointment with my PCP a week from now for non urgent care. New patient appointments are artificially delayed because onboarding a new patient takes longer than seeing a regular patient and to keep waiting times acceptable for current patients.