The time, labor and equipment involved is considerably more than what is needed for a typical virtual tour. Most slideshow tours are literally automated - it takes just minutes to upload your photos and generate a slideshow, throw some music in the background and upload it to the web.
My True Full Motion Walk-Through Video Tours take many hours to produce each 3-7 minute video, with editing, soundtrack, script writing and the recording of the narration. Also included is web video encoding, html coding, video compression and graphic design. In addition, I use high quality, licensed music on all tours, which generally run approximately $50+ per track. I have over $50,000 invested in my top of the line cameras, lenses, tripods, stablizers, sliders, compression software, server and computer power necessary to produce ultra high definition video as known as 4K video. Check on the web - most video productions for the web run $500-$2000 and up.