According to Owen, or maybe, according to what I understand from his email, overproduction of Ph.D.s is a myth. Schools can’t get decent Ph.D. holders.
Owen has evidence: CRA Stats.
More precisely, according to this table, 60% of CS Ph.D. holders go to a Ph.D. granting university (on a tenure-track or not?), 4% to a non-Ph.D. granting school, and 29% go in industry. A meagre 2% join the government, and 1% and self-employed.