I agree that folks are trying to compare apples to oranges.
Full-timing is different than traveling for vacations.
European travel and cruises cannot be done with a motorhome/5er/TT/popup/TC/class B/hybrid. If you want to go to Europe, you're going to go the same way everybody else does and leave the RV at home. And while you might take a cruise on you houseboat, this is about land RVs so that doesn't hold water.
I do a lot of local (within 4 hour drive) camping. Without the RV, I would drive my SUV and camp in a tent (no cabins available). I'd save the $20K i've spent on the clipper. I'd have many more miles on the SUV. Food, gear, campground fees, etc, would be a wash. So the RV is NOT a money saving expense.
Sure, depending on how you travel, you might save some money - eating in every night... but for some, part of the joy of travel is to try local foods, so that's not always a savings.
How much you spent on your RV will have a big impact on "cost effectiveness". The less put towards the RV, the better your numbers will be. And if you upgrade every 5 years, you're looking at an even bigger loss.
As others say, you buy an RV because you want to experience the lifestyle (whether camping, full-timing, snowbirding, or traveling), not because it's an investment opportunity.
And i'll add that many people bought houses in the recent past as "investments" and look where that got them. My personal feeling is you buy a house to have a place to live that you love - the rest is just icing.