This isn't "starting a software business" -- it's violating a lease.
Not everyone can or will take that risk.
In fact, many residential leases prohibit running a business out of the premises [0]. But these clauses are rarely enforced unless you're causing complaints.
[0] See clause 7 at https://cozy.co/blog/8-important-lease-clauses-for-landlords... for typical terms
I lived in a condo building that fined an owner $60k for 2 years of illegal Airbnb leasing (for a $300k condo).
I also had a friend who was evicted for leasing a rental.
Running a business out of the premises is rarely enforced, but it also rarely creates risk or loss for the landlord the way Airbnb does.
Housing prices in desirable downtowns are mostly distortion these days. It's been a long time since they corresponded to the cost of construction.