I don't know how much of that is "nobody to host" and how much is "keep people away from the house of the guy who may contagious."
But I do get what you're saying - I don't know who would host if Pete suddenly decided to stop hosting. Craig does a good job on the Universal show, but I don't know how he'd do on the Disney World show because it's a different format. Teresa did okay with The Trip, but that was also with JL and a different format.
I'm sure that if Pete and John want the show to continue even after they retire to Aulani (I assume that's what they plan to eventually do), they'll find a way to make it work, whether that means finding a host from outside the company or grooming someone from within to take over the podcast. Hopefully that day won't come too soon, though.