Is real estate investment as simple as it seems?

[Mike Tikh]

It seems to me that if you find the right combination of rental income (1%+ monthly) / cash paid, it's very hard not to make money.

Example: an $80,000 property, 25% down at 4.5%, and rented at $900/month.

You invest $20,000 cash.

The costs would be:
about $450 mortgage after taxes and insurance (assuming 2.5% property tax)
let's throw in another $200 in monthly repairs
let's assume I live remotely and have it managed by an outside company - $150/mo

$900 rent - $800 expenses = $100/mo cash flow

That comes out to 6% a year interest from cash flow and another 4%+ interest from paying off the mortgage over 30 years. That's all assuming no appreciation, no rent increases, not managing the property yourself, and what I think are pretty conservative expense numbers.

10%+/year for no work aside from buying a property and finding a management company sounds insane, and the return goes way up if you add a small % rent increase or appreciation. Where are my assumptions wrong?

Is it that hard to find properties you can rent for more than 1%/mo? People on here talk about finding properties in Michigan that rent 1.5% and higher all the time. Is it that hard to get financing? Are the expenses even more than I assume?

What is it I'm missing here? Because if all it takes is finding properties that aren't broken down and can rent for 1%+/monthly, then having someone manage them, I don't understand why everyone's not doing it. The return seems very high compared to many things out there.