Independent bookshops have struggled to survive since the abolition of the net book agreement and arrival of Amazon.
When I was younger, my friend's family owned a well known bookstore that specialised in a particular genre in a touristy area. It is still going but it only survives because of its reputation and they have turned it into a cafe that also sells books and gone mostly online.
My favourite bookstore, Arthur Probsthain, that specialises in Asian and African books, has suffered the same fate, despite being opposite the British Museum. It's now a cafe come art gallery with a few books as a nod to its past. Their book business is mostly online with a store at SOAS.
But at least they are still in business, unlike a lot of less specialised bookshops.
If you are going to do it, I would probably look for a niche where paper books are still popular eg cookery, children's books, cheap out of copyright books, and run it in conjunction with another business that will bring people into the store and generate revenue.