Claiming it blocks you from achieving your dreams is a false rationalization to quit something that you don't find fun or see the point of in your 19 yr old wisdom.

Look into BRRRRTHe trick here is that the cheaper you buy it, the more money you will make and have available for the "repeat" part if this strategy.See the problem with buy and hold investors is that they think Lead Generation does not apply to them.These investors for some stupid reason think that it is OK to buy MLS properties and they think Ohh my number calculations are very different from flipping or wholesaling.THen they buy houses the "conventional" way and after the 3rd house their debt to income ration is so high they are stuck.

Cognitive Biases or expecting everyone to make the same rational decision based on the same information.  

My Grand Mother was a deppression era kid and used to tell us about eating ketchup sandwiches pie coffee sandwiches, then, and later when goods were being rationed.  

Curious to hear your thoughts on why this happens, because I can't come up with a rational explanation for an appraiser to single out investors seeking loans as a class.

Now, sometimes passing on an opportunity is  rational and appropriate decision, but its more likely than not that they aren't doing it consciously. 

With higher cash flow on a 30 year, your debt to income ration increases with each property....

Am I just rationalizing a bad investment strategy here? 

Make sure you don't rationalize your answer to that question...just like you're rationalizing now.

Maybe I'm stating the obvious, but instead of trying to prove or disprove the 50% rule, I'm trying to rationalize why it would work so well.It seems that natural market forces will drive the expense ratio of a property to some sort of "equilibrium" that would be the same regardless of the region or type of property.