Everything is relative. We've spent the night in Walmart parking lots, rest areas, and even, a street in a city's industrial area, while waiting for an RV service facility to open the next morning. We just returned from 10 weeks in the San Francisco Bay area. Nightly was $95.00. Saved a bundle by paying $1800 a month. From what I read there are places that actually approach or maybe exceed $200.00 a night. And if that's your minimum required level of comfort, then the cost of RVing is going to be expensive.
Regarding depreciation, no argument that purchasing new or near new can bring the cost of RVing in line with paying for a hotel room. Maybe much more. But buying used can eliminate maybe 80% of that expense. And when talking about a new $300,000 motorhome, a first year depreciation of maybe $20-30,000 even amortized over a year is going to cost $55 - 75.00 a night. But that doesn't include the down payment and maybe 120 to 180 monthly payments of whatever the balance equates too. If you have the money and would like to drive a Newell or Prevost, $150 to $300 a day in travel expense will be pocket change. But honestly, what does any of it have to do with the cost of travel. It's like saying the cost of commuting is 50 times that of public transportation because I need to drive a Rolls to work.
You can make any argument you like. The cost is based on needs, wants and ability to pay. I have the ability to pay much more. But my needs are not great and I don't want to pay any more than I have to. For me, traveling is a means to an end. Getting out of the city an enjoying the beauty of the country.