I disagree. The same way a VC expects a few investments to cover the rest...they only need one rrapidly growing company to cover a downturn.
Any VC fund that doesnt diversify their investments to cover market movements wont survive very long.
Plus, even with a bubble bursting, commercial real estate in prime locations will retain much of its value. It will definitely outperform the startup market.
Are we talking about owning or leasing and then sub-leasing?
VCs that plan to use LP money to own and operate a commercial real-estate project are likely to get a "no, thank you", as LPs have access to REIT sector with much better purchasing power, IRRs, cashflows and operator experience.
If the VC firm is leasing and then sub-leasing, the reverse selection bias works against it, as the rapidly growing company is going to be the one moving out the soonest, needing higher square footage and shopping around for entire floors (or buildings, or campuses) will give it much better rate per square foot.
With that said, if anybody was doing it, it would be A16Z, considering how much Silicon Valley land and commercial real estate belongs to Arrillaga family.
Anybody doing that would almost certainly be buying high and left holding the bag when an economic downcycle arrives.