I played with upstrokes initially on bass - without a thought, it came naturally to me and I had a thicker sound with it. I only began alternate stroking ... naw that will only raise comments here, up- and downstrokes after I realized that there were limits in achieving the necessary speed for many licks. If I do it today, it feels weird.
Glenn, like many late sixties and seventies players, probably chose a pick to be heard better plus it was a request of many record producers of the time who found that a pick-played bass recorded more easily and distinctly. With today's technology that is of course a thing of the past.
The most recent incident I can remember is Black Sabbath's Eternal Idol from the late eighties where producer Jeff Glixman had the original bassist's (the Anthrax guitarist's little brother, Dan Spitz, a finger player) playing removed from the recording and brought in a pick player - Bob Daisley - to do the job uncredited.
I saw Squire only recently - loudest bassist I have ever heard in any band, louder than Lemmy. Make no mistake who is Mr Yes here. He's great and entertaining to watch, but also quite a bit sloppy live. He is not overly disturbed if he misses a note or two or speeds up in his licks. But it's all done with great panache.
