With any travel there is a certain (varying) loss of control, but I think what made so many people (me included) pay attention to the newer extra risks of cruise ships is when we saw cruise ships being stranded (in the sense of not being able to find a dock/country that would accept them), with the result being passengers were stranded (on board) for an unknown period of time.........in some cases with the virus spreading among passengers and crew. Then, as though that was not enough, (in some circumstances) then having to be quarantined before being allowed to fly home (and, of course, the risks of flying at that time).
If someone is land-based (either group tour or independent travel), things still can (and do) happen, but you are not necessarily as "contained" as one is on a ship, and you pretty much know where you will be (on land) and when/how (for the most part, with some exceptions in recent times) you will get home (or to your next destination).
If a fire were to happen at a hotel, there is risk, but one can also potentially get down the stairs and out the door quickly.....on a cruise ship there are lifeboats, but no just running off the ship by oneself. If a serious illness were to break out in one country, okay pay the fee to adjust one's airfare and hotel reservations and pivot.........not as easy in the more rigid arrangement as a passenger on a cruise ship.
We have enjoyed small ship cruising - and we have some incredible memories and have made some long-term friends - but it will be a long, long time before we sign up for another ship-based trip (if ever), and we will even be very cautious about deciding if/when future travels of any type may take place.
Everyone has different risk tolerances, and the key is understanding and operating within what is right for YOU.