Are you implying that Arlington does not have a real estate tax based on property value?
Otherwise it seems you are saying that Arlington should arbitrarily seize all profits from landlords because landlords are evil boogiemen.
It's worth noting that under this regime, any actions the landlord does take to increase the value of their particular use of the land is theirs to keep. Build a better apartment building that can demand higher rent? All upside is yours. Build a better storefront that entices higher end tenants? All the upside is yours once again. Seems like capitalist justice to me: you're entitled to what you've produced (value of things on the land) and the community is entitled to what it has produced (value of the land itself).
This feels extremely hand-wavy and borderline wishful thinking. Land value isn’t fully separable from improvements. (My land and improvements are both more valuable when my neighbors improve their properties. My neighbors benefit the same from me. I fail to see why we should be double taxed for the value we create.) Even is separable, it’s not at all clear that landlord profit could be separated this way, because landlords don’t rent out land.