I'm not sure that you have as much of a correlation as you might think Mike.
The vast, VAST majority of carpet cleaners do not do a dry vacuum step before HWE (and many before VLM...
).
I can't recall the last truck mount that came in for service that had a vacuum cleaner in it. Lord knows they have everything ELSE in the darn truck....but rarely a vacuum cleaner.
By virtue of that, you could easily see a large amount of cleaners buying wands in this price range that don't vacuum first, just because most don't, no matter what wand that they use.
When I was a younger man, cleaners focused on what truck mount had the highest CFM, lift, heat capacity, etc. In the past couple of decades, the majority of the machines, especially those made by the "establishment" manufacturers, all produced similar specs. Cleaners began to pay more attention to wands than machines, and looked for ways to increase production and reduce fatigue.
Machine types and wand types have little relationship to procedures, and frankly vacuum cleaners just don't have much sex appeal to most cleaners.