As a complete outsider to the USN (other than pulling to Navy bases on occasion while assigned to a cutter):
The Mids will be fine, regardless of whether or not they get to experience the "real Navy." I'll just put this thought out there: every year, 50,000 sailors depart Recruit Training Command Great Lakes for units around the world with no fleet experience and select job specialties ("rates") without so much as a few basic explanations from their recruiters. Certainly, if they can do it, then we can expect the future officers that will be charged to lead them to do the same. Those same recruits don't get a "2 for 7" opportunity, they sign on the dotted line and commit to at least four years (in most cases) right off the bat.
You commit because you already made a commitment, regardless of whether or not you had the opportunity to go on a couple of training cruises. If not having that opportunity is causing you to rethink your situation, then I respectfully question that person's commitment in the first place. These extras are simply that, extras - just as much as USCGA cadets' experience on EAGLE and summer cutter experiences are extras. They are nice things to have, but there is very little that can't be taught using other methods while at USNA or immediately upon reporting to their first unit after commissioning. Of course, it's absolutely crushing to not get to have those extras, but they will be stronger and more resilient for continuing to weather this storm.
At the end of the day, the question is not about expendability, but about sacrifice. The goal right now is to maximize the health and safety of all midshipmen, at the SACRIFICE of some of the experiences and moments that were once norms. I guarantee no one is sitting around discussing the expendability of the Class of 2023. What they most likely are discussing is what can be done now to ensure their health and safety, and what can be done at a later date to make sure they receive the necessary training to commission. If you want to be cold about it, if for no other reason, the USN (and taxpayers) have already invested a ton of money into that class - they're not looking to sabotage them when it's in the Navy's best interest to ensure they succeed.
Edit: I'm still thinking about this and I must be on my soapbox tonight so...in addition to sacrifice, it's also about perspective. If you want to talk about real sacrifice in the military, think about the thousands of servicemen and servicewomen around the world whose return from deployments were indefinitely halted. Some of those people are just just NOW coming home. We're talking people who have been deployed for over a year at this point, missing more life moments and milestones of their families and children then they had anticipated. That's a real test of adversity and resilience. When you compare the two, potentially having to stay at home and take virtual courses is a small price to pay. So, please parents, have faith USNA will take care of your "kids," who are adults and will adjust to what their employers require of them just as the rest of military has done.