I've never personally worked in an independent pharmacy, but there's only two instances that I've seen an independent survive more than 5 years. The first in is a rural setting. As others have mentioned those settings really take off if you partner/connect with a clinic or the local rural hospital (either be close by or if possible rent some office space from them). I know it's the bane of pharmacy but.....I'd highly recommend having a drive through be part of the pharmacy. It'll really increase your numbers. This is America and people want and will pay for convenience. They got their McDonalds in the passenger seat and they wanna pick up their diabetes and blood pressure meds on the way home and still have their McDonalds be warm by the time they get home D@*# IT!!! To counteract your employees hating the drive through, I'd have a really nice break room (and actually allow/enforce breaks). Put in some nice couches and tables and have cable tv on a nice flat screen. Your employees will notice/appreciate the effort.
If you're looking at more urban setting, I've only seen a specialty pet pharmacy last more than 5 years in a metropolitan area (and they weren't just surviving, it seemed to me that they were killing it!). MOST people don't have med insurance for their pets, so it's run more like a normal business where you actually set your margins instead of fighting insurance for reimbursement. I believe the pharmacy I know did stereotypical pet meds, and both sterile and non-sterile compounding for pet meds.
A couple of other options for OP to look into are 340b and North Dakota. I don't know a ton about 340b pharmacies, but most of the 340b pharmacies that I've encountered seem to be in the green for their spreadsheets. And North Dakota was one of the few states that had the foresight to see what corporations would do to our profession and so long as it hasn't changed in the last few years, you can't own a pharmacy in North Dakota unless you are a licensed pharmacist. So chain pharmacies are non-existent in North Dakota. You'd be competing against other independents, and I can't see there being many independents having multiple locations because who are you going to sell to when you retire? You'd have to sell them off one by one because no pharmacist is going to have millions of dollars to buy your empire of pharmacies when you retire.
Anyways, best of luck to OP!