I disagree with several of your points:
The numbers that pop out of your calculator when you discuss ROI are important, but keep in mind that a home pays you in TWO WAYS: (1) You get the practical use of living in it, and (2) your house is increasing in value. Though exceptions exist, it's reasonable to think that you can live in a house for years . . . then sell it and get back what you've spent. In contrast, at the end of a rental contract, you just get a nice goodbye from the landlord.
The stock market may go up and down, and the value of your house may do the same . . . but it always remains a useful investment. That is, if you chose poorly, your 150K house may decrease and now only be worth 100K, but you can still live in it. In contrast, if your mutual fund dips, you're poorer than you were.
The cost of buying vs. renting fluctuates wildly, but in my area buying a same-size house is usually slightly less expensive than renting an apartment.
Renting is NOT a fixed expense; rather, once your lease expires, your landlord may decide to increase your rent. In contrast, if you have a fixed-mortgage, you're still going to be paying the same amount 10, 20 years from now (unless you pay it off earlier).
Yes, owners do have to be prepared to replace a roof or a furnace, but the reality is that renters are paying these expenses too: It's just less transparent. If you were a landlord, wouldn't you include the cost of future repairs in your rent? You'd put X amount of each month's rent away into an account so that when the water heater quits working, you'd be ready to replace it!
I agree that everyone should diversify his or her investments, and a house should not be the lion's share of anyone's portfolio; however, the better argument here is that you should buy a small, inexpensive house -- not that you should avoid real estate altogether! Incidentally, my house makes up less than 5% of my total assets.
6% realtor fees is outrageous (though that may vary from place to place). The standard is 3%, and although I've owned two houses, I've never paid these fees. It's not hard to buy a house without professional help. However, you will need to go through a lawyer's office to make the transaction official (to protect yourself), and some other fees are unavoidable.
I have to agree with you on a couple things:
Home maintenance and repairs does take time and does require learning additional skills.
Home ownership does reduce flexibility. An apartment dweller who suddenly learns he's having triplets IS in a better position to move quickly than is a home owner.
And I'll bring up a couple other points:
The big one first: You're arguing the difference between renting and paying a mortgage. You're ignoring the biggest benefit of all. Eventually the home owner gets to quit paying his mortgage, whereas the renter must pay every month . . . forever. Take me for example: When we married, we bought a small starter house and paid it off in eleven years. Then we sold it and moved into a larger house in a more convenient neighborhood -- and because we'd lived frugally all those years, we were able to pay cash. So we haven't paid rent or mortgage in more than a decade. With that large line item removed from the budget, we were able to travel much more while all our kids were still at home, we are currently able to pay for their college educations without trouble, and we did those things without skimping on saving! Yes, we do still pay maintenance and we do put in time on the house; however, we tend to spend about 3K a year on maintenance and a little over 1K a year on taxes and insurance.
The best deal isn't renting or owning a mortgage: It's owning a house outright! That allows you to live on less so that your dollars stretch farther each month, which is a different way of looking at reaching FI.
With a house of your own, you tend to have more space and more control of that space. I never lived in a rental that had more than one living area, yet when both our children were still at home we definitely enjoyed having a living room and a den. I never lived in a rental that had adequate storage. And in your own home you can paint your walls any color you want or have a trampoline and a dog.