VFD has been around for years in industrial apps, but it is just now showing up in residential HVAC apps.
Its not the refrigeration technologies, other than much higher efficiencies, but rather the change in refrigerants with the changes in pressures and oils in residential HVAC stuff. This change is not new, its been in the works since 1989. Granted, there is a large portion of the "techs" out there who only have a ticket book, jug of gas and set of gages don't know or understand how a refrigeration system works or why it works that way. My company gets called frequently to straighten out their messes because the home owner tried to get it done cheap, instead of calling a licensed, insured, professionally trained, master HVAC tech.