Any calculated or actual cost for either method of travel put aside, there's a huge difference in what each provides or encounters in total.
With conventional travel, It's pack and unpack so much and so limited on what you can take along and just using of a basically public beds, bathrooms, furniture and the slot parking area at the motel/hotel etc. Your receipt that's different after you return is just that it is a receipt for the costs and even if you have or had the same destination experiences at the places of interest venues as when RV'ing. Eat out for most or all meals and that's not cheap and comes with no actual control of what ingredients or quality or freshness of the ingredients is.
RV'ing is the same as taking your home with you to exactly where you want to go and having all your clothes, food, and other items where you'd put them when you left your S&B home. No packing and re-packing, total control of the foods you ingest, a bed/bathroom/furniture only you have used or will use plus take along any and all items you logically want to. You pick the place you desire to stay at and if you don't like it, simply drive the rig to any other place or CG of your choice. Most CG stays are a big part of the fun when traveling with the like thinking other RV'ers all around you.
Just try doing or having some of the afore mentioned attributes or functions or abilities with conventional travel? BTW, when you get back home, you still have the RV for additional ventures and not just receipts or bills still to come in. If you don't want to travel any more with your RV, you still have something of value to sell.
Ever try to sell a receipt from a motel, hotel, airline, car rental, etc? Good luck!
It's really a "no brainer" if you really think about it!