Campuses have been empty because there are no classes! You can't bring everyone back and have social distancing at the same time, there is not the room. Even in normal times, finding space for every module is a nightmare.
You can only bring some classes back for f2f so you have to prioritise. Universities are rightly giving preference to any practical course, where students really need f2f. But after that, who do you give preference to? Are law students more important than literature students? Does the econ department get to come back because their head is chums with whoever decides these things?
When schools went into lockdown, a lot of parents said, why can't you keep the schools open and just distance the kids? And teachers said, don't be stupid, we don't have the space. Well universities don't have the space either. So as long as social distancing is the rule, you can't be 100% back to normal.
Hopefully social distancing will end this summer, but if there is another wave it will surely be brought back and then universities will be caught out. That's why our plan is to move large lectures online, that opens up enough space so that all smaller classes can be f2f all year even if we have to go back to distancing.
Large lectures are not as popular today anyway thanks to lecture capture, in some departments only 10% of students show up and the rest watch it online anyway. And to be clear, if you take a large lecture class you also have a small seminar class, and those will definitely be f2f next year. So everyone will have f2f for all or most of their classes.