Now I respectfully disagree. Come April, the top schoolsa are competing for a small pool of highly coveted applicants. Schools would like to start courting those hot prospects on interview day by wowing them with meals, tours, and engaging presentations. This is particularly true if the school is in a city many students have never visited. For that reason, as well as for the advantages that might be gained by a face-to-face interview, some schools will want to go to in-person events. That said, there could be some pressure from the accrediting body to ditch the in-person interview as elitist and a barrier to the recruiting of a diverse student body and some schools will bring this up in their next self-study as a step they've taken to be more incllusive in their admissions process.
I hope you're right! What you are describing at the end of the cycle with top schools jockeying for top candidates, however, is not the issue and doesn't address the concern regarding the cost and inconvenience of having to take time off from whatever to travel to distant cities so schools can size us up in person, without us knowing whether or not we will even be wanted at the end, let alone be wooed. Don't schools already address the diversity issue you raised by covering travel expenses for some candidates? I don't know about med schools, but I know UGs do that for diversity candidates during second look days. Some UGs (even state schools) do it for high stat scholarship candidates, so I know for a fact there is money for this!
Schools can absolutely do the hard sell at the end without in person activities on the front end. As you well know, it's hardly a one-way street, and top candidates won't write off a T5 or T10 school at the end, without a second look, because their interview was virtual rather than in-person. Speaking as a future candidate, I'm pretty sure reputation, opportunities, match lists, location and, last but not least, money, all play far greater roles in ultimate decisions than superficial niceties during meals and other recruiting events. At least they will for me, assuming I make it that far.
It would be AWESOME if schools said that virtual worked this year, so let's change the system, but, given how the entire process seems to be designed with the schools' needs in mind rather than the applicants' (including the wining and dining at the end), excuse me for saying I'll believe it when I see it. I'll be applying next cycle, so it would work out great for me, but I'm not holding my breath. I'll be praying for the opportunity to take the time and spend the money to accept as many IIs as I can get, but, yeah, virtual IIs would work far better for me as a recent grad with a limited ability to take time off from whatever I end up doing, and to spend what little money I have to try to score a med school A.