These places tend to be connected to useful infrastructure like rail lines, and at least in the US, the internet kinda borrowed rail's right of way to lay fiber. Not sure how well connected malls are; they tend to be near highways so it might have a similar advantage?
Tech enabled homes, for example. Converting malls into homes, and managing building complexes using a tech stack...
If you really can't figure out one single use for cheap empty space, man, you need take a step back and just play around with your imagination a bit :)
I can think of plenty of uses of empty space. Housing is just one of them. What I didn't come up with was any need that tech companies might have. (I hadn't thought of datacenter, which another commenter mentioned, but I doubt the space opening up will be particularly useful for that.) Regardless, I've not heard of any tech companies needing huge amounts more space recently. Starting a new housing company to use this space might make sense, but I doubt any of the tech companies have any desire to become housing companies. I guess I could be wrong. If they do, I'll be removing any investments I might have with them, though.
