For a 5'x 75 ft roll of color change wrap material it costs around $750 plus shipping and tax. For full coverage of a 40 ft motorhome you'll need 2-3 of those depending on usage and seams. That puts you at an untaxed and unshipped cost of $1500 to $2250 for the cost of the material alone. Then the installation cost maybe anywhere from $3 per square foot to $12 per square foot depending on what all is required. This may include cleanup and decal removal and adhesive removal, perhaps even equipment removal depending on what's in the way.
On the other hand there is smaller decals and they can be replaced easily using plastic razor blades, heat, and a good adhesive remover like rapid remover. A clay bar can help smooth the surface to prepare for wrap.
The benefits of a full wrap can be observed in the timely removal of the vinyl and good treatment of it as well. Other factors would include sealing off edges with silicone to promote longevity, covering it to avoid sunlight, never parking it in the same direction everyday, little things like that. But the key to wrap being a benefit is the removal before it begins to crack or fades. Once the vinyl begins to crack it can have an effect on the paint underneath.
Vinyl graphics are not a paint replacement. Paint is superior and has greater longevity without contest. Paint covers areas which vinyl graphics cannot. But there are such a wide variety of vinyl graphics such as carbon fibers, chromes, metallics, and color shifts that it does present a viable option to many. And while paint is superior to vinyl, vinyl is useful in protecting paint from UV, dust, minor scrapes & scratches, chemicals, and even some dings.
Wrap final has been improving from its conception. I've worked with vinyl for 22 years and have been witnessed to the changing technologies. There are bad vinyls and good vinyls. Experience helps you determine what's what.