Assuming the market returns 10%, of course borrowing at 3% and investing at 10% makes sense. But that's a big assumption.
I'm in much the same boat you are in that the vast majority of my net worth is in stocks. I view rental real estate as a vehicle to build another income stream. I'm not in any way saying I think real estate returns will be superior to (or for that matter, inferior to) equity returns going forward. But I do think comparing income only on one asset class to total return on another is an apples to oranges comparison, as is comparing returns on two cash flow streams of vastly different risk profiles.
You know your risk appetite, you know what the rest of your investment porfolio looks like, you know your own cash flow needs and retirement goals. Nobody else here knows any of that. Bear markets happen, if returns always equaled their historical averages we'd all borrow at 3% and invest at 10% into perpetuity and we'd all be billionaires, straight line assumptions in a spreadsheet don't always play out in reality.