> I'm not seeing how you get from share buybacks to a shift in priorities in corporate research

seems to me investing in your own company:

before: use funds actively for research and development

after: use funds passively to "invest" in your company by buying stock

seems like that old parable where someone buries their investment.

EDIT: parable of the talents

https://en.wikipedia.org/wiki/Parable_of_the_Talents