A few of the units around me dropped their prices, but even then they wound up renting to people that I rejected due to any number of reasons, so the season has definitely thinned the pool of good prospects.My units show well and are all updated, but I have fairly high criteria (650+ credit, non smoker, 3x rent) so it may also be a factor.

The hard part is factoring in the time to acquire 100 doors on your own. 

Labor rates and service calls are getting quite pricey and for folks that cant do the repairs themselves they need to factor those expenses into the overall deal.

I have to factor this in so my bid is low - but everyone else has to do that also.  

Basically the biggest reason someone might use a shipping container as an ADU is for the "cool factor."  

I know it can be a risky investment with the inability to acquire title insurance and all... what other risk factors have any of you come across?

Do not dismiss the "encouragement factor" that you will derive, simply by being around people who are already doing the exact same thing, that you are trying to do.  

However if you do want to factor in appreciation and rent bump ups it becomes a different question.

My family's farm is multi-generational (currently 6th generation, to be exact), so I have been exposed many of the aspects and tangents of RE via involvement with the family business including generational wealth management, land acquisition, rental homes, tenants, etc. 

the problem is that its in HOUSTON, ok now that the joke is over..i think you are dealing with a lot of factors that are working against you.