Even most successful entrepreneurs do not change an entire industry. But that’s exactly what Steve Jobs did to personal computing — three times.

With the Apple II, Jobs made personal computers useful. In the mid-Seventies, home computers were build-it-yourself hobby boxes, useful only to the nerdiest nerds. By the time I entered middle school in 1981 there was an entire lab filled with Apple II Plus machines, and lots of fun software to run on them. The first computer “clone” wasn’t Compaq’s copy of the IBM PC — it was a clone of the Apple II. An industry was born.

Three years later Jobs made the personal computer approachable with the Macintosh. He didn’t invent the GUI or the WIMP metaphor but he and his team made them useable and affordable. What most computer users took for granted in 1995 was deemed a “toy” by many critics when the first Mac arrived in 1984.

And last year, Jobs made the personal computer ubiquitous with the iPad. This third revolution is only beginning, yet still many critics deride this “toy” as a “media consumption device.” I do most of my photo editing on my fat, slow, first-generation iPad — and I’m outlining a novel on it, too. Others use it to create music, paintings and video. That’s some “consumption” going on.

In the meantime, Jobs also:

• Created the first “event” Super Bowl ad
• Reinvented the cell phone
• Revitalized and reinvented movie animation with Pixar
• Brought low the old, thieving record labels
• Started from scratch the largest music retailer
• Changed the way people buy, keep, travel with, and listen to music
• Created a physical retailing empire with greater profits-per-square-foot than Tiffany’s
• Apple is currently making people (and the competition) rethink the laptop computer with its diskless MacBook Air

Oh, and Jobs by-the-way took the helm of a computer company that was just months away from bankruptcy and turned it into the world’s most profitable and valuable computer maker, consumer electronics firm, and cell phone manufacturer.

Good lord. Any one of these many accomplishments, and Jobs would be hailed as a titan of industry. You may or may not be an “Apple person,” and the way you work, play and compute have all been deeply effected by the man in the black, mock-neck sweater. From your Windows 7 all-in-one computer, to your Acer Timeline ultra-lightweight laptop, to your SanDisk MP3 player, to your Android smartphone or your Samsung tabletnone of them are made by Apple and all of them adhere to the vision of Steve Jobs.

That’s an astounding legacy, unparalleled except perhaps for Henry Ford.

Poor health is certainly what prompted Jobs to resign yesterday as CEO of Apple, Inc. Nobody knows how long he’ll have to enjoy his retirement — but he’s earned it like no one else has.

So, thanks, Steve, for all the insanely great stuff. Thanks also for leaving Apple in such capable hands. But thank you most of all for setting an example that never failed to inspire.