Future of renting SFH

[Tim S.]

I'm in my 20s, live in my own SFH that is nearly paid off and looking to buy my first SFH rental property. Over the next couple years I would like to own about 10-20 SFH. I work a full time job so these rentals would be more of an additional income, safety fallback in case something happens to my current job, and most importantly retirement income. Although I know it's impossible for anyone to know the future this is more of opinions and guessing. My question is what do people think about the future of owning many single family homes? Are there threats that would make owning and renting SFHs not profitable. (Political, government influence(taxes/fees), population/homes available) What about in 30-40years?