I’d also think it’s an economic thing. If those companies already have sprawled-out office parks from the 70s and 80s, it makes more sense to keep renovate what’s already there…
…that is, unless you want to kick out every employee there, tear down all the existing buildings, and spend millions to rebuild everything from the ground up.
(That might make sense if you get to the point where retrofitting would cost too much, or there’s something like asbestos involved. If you try to step into IT/biotech companies’ shoes and see what they see, I’m not sure if that’s their first instincts for a good investment)
With that said, if Apple starts a trend, then that might encourage companies to make their campuses more urban and compact from a recruiting/amenities perspective (as is the case of Parmer) -but that’s just hopeful speculation more than anything based on facts and truth.