But interestingly the disruption that eliminated travel agents, and replaced stock brokers with asset gatherers, and decreased stock market trading costs from 2-6% to 0, will finally gain hold in real estate.  

Holding this property longer will decrease that profit (as in losing money) by the day.

Focus on increasing income and decreasing expenses.

I can't decrease it, but I can avoid adding to it. 

Even conforming lending is decreasing risk appetite.

It's like a muscle... the more that you use it, the more you'll be able to wrap your brain around it and set the intended parameters.

In addition to DOM going up I'm seeing values decrease/stabilize in certain pockets.

While the monthly payments would go up (without renting the ADU), you may find your overall expenses decrease as you don't have the repairs.For your current home also think about upcoming major expenses (eg roof, furnace, etc).

The motivation to provide new units decreases.  

. - Know if the population is increasing, decreasing or has remained flat, where you're buying.