Eventually saving on your own to get the next, third, fourth ,whatever property becomes a headache/chore/seemingly impossible.

So not entirely impossible, there are properties that work with the numbers, just a lot of people trying to get them.  

Not to mention 5 daily showers running up the water bill, the 5 cars they drive and make parking impossible for neighbors.

One thing to note is that is generally harder to go from SFH to MFH, but not impossible.

It may make evictions of non-performing tenants difficult or impossible.

It's not impossible, but you've got the odds stacked against you.House hacking is by far the best way to get started.

True.....but I would be wary of them because they do not take into account two of the most important factors: 1) Reno budget - this is critical to get right and the cause of most failures. 2) Time - it is near impossible to calculate this accurately, too many moving parts...Still, thay can give the prospective investor a ballpark idea.....I have never, in all my years, seen even 1 of these "flipper calculators" that I'd say even touches on "ok". 

.  :-) They are doable lol, but I always prep clients that it is not going to be fun for either of us, and I have done enough of them to know which ones are possible and which ones are near impossible. 

It's impossible to know for certain what youre facing without knowing all of the specifics of your situation.I am not a tax professional, and there are any number of variables that will affect your specific outcome and make generalized advice either not applicable or even counterproductive.

so this is basically impossible on LTRs.