Commercial leases don’t generally work that way. A typical term is 10-15 years. There will be built in annual rent increases but the landlord doesn’t come back in year 5 of a 15 year lease and increase the rent. What happens is that the market changes over that term and by the time you come to the end of the term, the market has changed dramatically. That’s what is happening to many businesses. Rents in NYC were very different 10-20 years ago.
The fact that the owner has a mortgage or not doesn’t change what the rent should be. Why should it? If that was the case, you could argue that someone who owned their home should be paid less at work than someone had a mortgage on their house for the same job. The rent is what the rent is supposed to be for the space.
