Some stay because they have children doing well in the school system and do not wish to disrupt that.

Marcus,Don't expect the tenant to cooperate, and in fact, expect a battle if they are paying below market rent and you disrupt them.If the seller is calling you they are motivated. 

I remember 20 years ago saying why should I get my real estate license the internet is just going to disrupt the agent model just like travel agents.

Adding central heat and Air to a 12 unit could cost a lot of money and be very disruptive to your tenants unless duct work is already running through the walls.

There is a lot of commotion and disruption.

Perhaps if you were starting a  tech company with the opportunity to disrupt some aspect of RE, that would be of interest to angel investors or venture capitalists.What are you bringing to the table?

But when it's all over, you have to surrender your property.https://en.wikipedia.org/wiki/Eminent_domain_in_the_United_StatesThe examples I cited my be less violent than Molotiv cocktails (or major storms, earthquakes, or volcanoes), but they still have the potential to disrupt one's life in a major way.

You won't be disrupting a tenant now vs. later.

@April VogtI would first start by offering to let them leave so that they can avoid the renovation process and constant disruptions that will be annoying to them if they stay.

The normal flow of property tours, due diligence, closing processes and more are all being disrupted by social distancing policies, travel bans and other complications from COVID-19.