why wouldn't you just price discriminate through short-term concessions to fill the remaining 20% and increase revenue? this seems to be what most apartment buildings around me actually do.
That is what people do sometimes (esp. in SF where you'll get "2 months free rent"). But I think in commercial real estate the math is a bit different because leases tend to be longer - so you really don't want to budge on the actual monthly rate and even 1-2 months free doesn't end up helping the prospective tenant that much
