I’ve lost some students, but we’re still doing ok financially. I haven’t been able to spar since March 2020, though as the guidelines in England eased up on 17th May, I have at least been able to run non-contact classes again (I’ve been running classes over Zoom until then). In England, sparring is due to be allowed again from the 21st June, assuming there isn’t a delay to further lockdown easing.
I know that there are local schools which have been running. I’m not sure if I’ve lost students to them, but frankly, I don’t care. If a student of mine wants to train during a pandemic against national health guidelines, then that isn’t a student I want training at my school. If they ignore health guidelines, then they are a risk to everybody else at the gym.