"Tech" is so broad. Some tech sectors are by their nature location agnostic and can easily exist in a remote/hybrid work environment. Fintech, adtech, consumer-facing app+services, and general back end development largely fall into this group. Chicago can encourage remote work or even full relocation in these tech areas and likely find some success.
But other tech sectors, specifically med/biotech and robotics/nanotech, are super cluster-oriented by necessity. Remote work isn't that viable for most roles in these verticals. And the clustering benefits compound over time: the percentage of biotech and nanotech VC going to Boston/Cambridge, Silicon Valley, NYC, and San Diego has only increased the past 20 years, even as many other cities have started biotech incubators with generous tax incentives. (Homer Alert) Boston in particular
keeps distancing itself from the rest of the pack. Biotech is incredibly capital-intensive, takes decades to pay off (if it ever does - plenty of products never make it past trials), and needs a steady pipeline of highly-specialized labor.
I'm not saying Chicago couldn't start a biotech incubator, but it's a little late to jump into biotech and medtech and expect payoff commensurate with the startup costs and time until investment return.
I bet AI and logistics would also be ideal high-value tech sectors for Chicago to nurture, and both are more "open" than biotech/medtech.