$10k gets you $32 a month, roughly. And that's not even an especially safe rate of return - true fixed income would be closer to 4% before inflation, i.e. 2.5% after inflation.
I know of it, and I think it's optimistic. You have to factor in the chance for inflation to go up and general equity returns to go down. I think 7% nominal returns is an outlier in the history of the world.
For example, the 30 year TIPS return at the moment is ~1% - I would consider that a truly "safe, real interest rate" return. By that standard, taking out 4% in real dollars has a significant chance of depleting your principal over time.
Picketty's "Capital in the 21st Century" gives ~5% as the historical rate of return of capital after inflation, which is remarkably consistent across countries and decades.
a robo-adviser I am using "assume[s] a return of 5.1-5.45% on stocks and 0.74-1.05% on bonds after 0.5% fees". I do find these numbers a bit pessimistic but at the same time, I would expect the robo-adviser to give more optimistic numbers than pessimistic ones.
