I'm with you on 4 for a certainty.
#5 has propelled our industry into becoming "cleaning services" and no longer "carpet and upholstery cleaners". When my father was in the first decade of his business in the 60s, he cleaned hardwood floors, area rugs, upholstery, washed walls, and as the decade progressed, wall to wall carpet cleaning.
He bought his first hot water extractor when I was 9, and is first truck mount when I was 14. Both were because of the widespread use of synthetic fiber, wall to wall carpet. Had that era been like ours now, I'm not sure he'd have ever bought a truck mount, or perhaps even a portable.
Interesting point:
Wall to wall carpet is coming back
Get expert cost estimates, material recommendations, DIY advice, and more.
www.housebeautiful.com
You'd be surprised how much of it is wool, and how many carpet cleaners with no past experience now call me and say: "I just presprayed this carpet, and it stinks....WTH is going on?"