I've thought a lot about this, and have simply concluded that we don't really know what the commuter market will be like in a year's time. Let's assume, and hope, that a year from now restrictions have been lifted, and the economy completely reopened. You raise some good points, and I agree there will likely be a significant reduction in those using public transport to get to work, but I also believe peak time demand will pick up again, as some people will return to offices, though never to the levels it was pre covid. For some the prospect of never again having to cram on to the 48 (for example) and sit in Bristol's rush hour traffic twice a day is almost too good to be true, but perhaps it might at least make the experience for those who do return more bearable. But it is also true that many bus routes exist primarily for their commuter traffic, (everything else is extra), and routes such as the aforementioned 48/49, 1/2, 75/76 have benefited from investment over the years, and as such, certain routes might decline, which, as both an enthusiastic and advocate of buses, is concerning.
Off peak travel will likely return to what it was, and routes such as the 17 will also likely go back to pre covid levels, as that tends to attract shift workers, many of whom can't work from home. Just some thoughts anyway, but as I said, we won't get a true picture of new travel patterns for at least a year.