I think one other thing is prices of STR have gotten so high along with ridiculous add on fee's folks are going back to hotels as well. ????

To add on to posts above, I am not sure you can cross-collateralize a mixed-use property with residential assets (SFR, 1-4 unit), since residential assets are securitized as different mortgaged back securities than commercial assets. 

My calendar stays full and for top dollar so I do not need to add one as the return on investment would be near zero.

The few I have talked to are franchises with little to no reviews or they have add on after add on fees.  

To add on to what @Flash Alexander laid out.

It may sound nice to pay a 5% management fee but the extra fees can add up to be more than the other company that charges 10% with no add-on fees.

The problem is there is a lot of add on's and we can't build a relationship with the renters.  

All my cash flow is put into maximum overfunded permanent life insurance.That is the equivalent of a savings account that brings between 4.5 to 6% return, is asset protected against creditor, is transferred to your heirs tax free and also as an add on gives you a cushy life insurance coverage.

In addition, I want to add on to my portfolio.

I would charge 1 month and add on more for pets depending on type of pet a flooring.