I think I read somewhere, it was the record company's (or something from the business side of Journey) decision to add Steve Perry to the band in the first place, and that didn't sit well with the band.
From what I understand, they (the business people) wanted a commercially successful band.
Don't how much truth there is in it, though.
I'm not much educated on Journey before the Perry years, other than knowing Schon & Rollie rolled with Santana.