YES, you have a much better haircut than most people who still have all their hair, it is clearly not an amateur haircut and when i first saw this photo in another thread i thought i'd probably look twice at it if you passed me in the street.
I wouldn't say that i'd have no idea how to approach doing a cut like yours, but it would be a stretch for me, it's definitely not something i've attempted.

My haircut is perhaps not as complex, but it is a little quirky and edgy and i've done it every few weeks for years whereas a stylist won't have nearly as much experience doing that particular cut. I do mess up from time to time but that's mostly just when i'm in a hurry and easily avoided with a bit of caution (and when i do mess up, it's usually carelessness doing something easy around the contours, like edging up the back and sides or tapering around the ears).
I really love my haircut whereas i've never once had a professional haircut that i liked... even when i've brought photos, they never seem to understand what i want and i feel the need to have more control over it than that.

Could i ask you to please elaborate a bit on the differences between blending a system vs. growing hair? You only get one shot, i know, but otherwise?
Anyone else on the "little tricks and idiosyncrasies"?
I gather from what you've said that if you wanted the exact same haircut you gave yourself for years, you'd still go to a pro?

thx again.