>>127175601>>127175647 is right, Blackmore never worked with bad musicians in Purple or Rainbow's original run. The only time when the quality of musicianship started slipping a bit was in the 90s version of Rainbow and even then those guys were still fairly good musicians, just that Blackmore didn't want to pay for/deal with the headache of having A-list guys anymore.
I mean just look at the string of vocalists he basically either discovered or whose careers he took to a new level in the 60s through to the 80s - Rod Evans, Ian Gillan, David Coverdale, Glenn Hughes, Ronnie James Dio, Graham Bonnet and Joe Lynn Turner.