Dan Hendrycks (note: my employer) and Mantas Mazeika have recently covered some similar ideas in their paper X-Risk Analysis for AI Research, which is aimed at the broader ML research community. Specifically, they argue for the importance of having minimal capabilities externalities while doing safety research and addresses some common counterarguments to this view including those similar to the ones you’ve described. The reasons given for this are somewhat different to your serial/parallel characterization, so I think serve as a good complement. The relevant part is here.
Dan Hendrycks (note: my employer) and Mantas Mazeika have recently covered some similar ideas in their paper X-Risk Analysis for AI Research, which is aimed at the broader ML research community. Specifically, they argue for the importance of having minimal capabilities externalities while doing safety research and addresses some common counterarguments to this view including those similar to the ones you’ve described. The reasons given for this are somewhat different to your serial/parallel characterization, so I think serve as a good complement. The relevant part is here.