Two points: (1) Dyson took a long time to make this vacuum work and went through howevermany prototypes, i.e. his major innovation was made possible by many minor innovations (2) Consumer Reports rates the Dysons right in the middle of their lists.

Aside: my mom spent the big bucks on a Kirby and put me and my brother to work. Vacuuming stairs with that thing was an absolute nightmare, I think it weighed 35 or 40 lbs.