Neither player's addition drew nearly as much scrutiny as quarterback-related moves would have commanded before each team settled on long-term starters.
That is the point. Both moves say good things about how each team feels about its quarterback situation overall.
The emergence of Russell Wilson in Seattle and Colin Kaepernick in San Francisco removes pressure to develop alternatives. It renders backups for those teams about as relevant as the ones St. Louis has employed since making Sam Bradford its undisputed starter in 2010.
Quinn is not the next Charlie Whitehurst, Tarvaris Jackson or Matt Flynn in Seattle. Those players had realistic shots at starting. Quinn does not. McCoy obviously isn't going to push Kaepernick for the starting job.
So, pending these moves, both teams could still select quarterbacks in the later rounds of the upcoming draft. There just isn't much urgency.
The chart below shows five-year stats for quarterbacks projected to be second on their teams' current depth charts.