Portfolio = Income derived from financial instruments like dividends (including REITs), interest, royalties, and capital gains.Mostly income w/out loss potential, and favorable tax rates.Cap losses may offset cap gains w up to $3,000 loss.

Since you cannot predict what things may cost 10 years from now, its not really useful in my opinion to get too detailed trying to analyze the way you have here.

The document or whatever instrument allows this would ensure that the obligation to pay for the mortgage and expenses (Taxes/utilities/maintenance etc...) falls to the corporation and not myself and would be paid directly by the corporation so as to not look like income in the form of a transfer from corp to me to lender. 

It's difficult trying to predict where the rates will go.

What if appreciation and the prediction of appreciation was the metric to be used over the hold period?

My grandmother lived there for many years when I was growing up (I always think of the massive shark head store there), but I don’t think even she would have predicted how much it would rise.

An owner trades the predictability of a low Flat Fee (which is typically charged every month whether property vacant or occupied, tenant paying or not), for less PMC alignment with the owner's interests.

However, this comes with the risk that market conditions or interest rates could change, making refinancing or selling more challenging at that time.On the other hand, a conventional 30-year mortgage offers long-term stability and predictability.

The thing about reserves is that you can't predict when something will break so you could be way off if you do calculations on life span.

But we do have a few other things we didn't have ten years ago: A historic housing shortage caused by 15 years of under-development and driven by a demographic shift (demographic changes are as predictable as time itself), very high purchase and rental demand, and continued upward pressure on rents and prices.I agree with you that in many ways it has gotten harder to invest.