As for the seals I think you are mistaking the usual standard fitted OEM bearings for something with a bit of quality. Most are not
Which manufacturers fit bearings without seals? I’ve never seen this.
As for jetwashing grease out of bearings – this must be some kind of ‘special’ maintenance routine by the mechanically clueless. I can attest that a bit of common sense and a jetwasher does NOT remove grease from bearings or cause their premature demise. Of course, no-one in a bike shop is ever going to be able to tell if a bike has been jetwashed with no ill effects, cos the bearings will look the same as normal non-jetwashed bearings…
