HHH started dating Stephanie McMahon around Dec 2000
He was already a 3 time World Champ by then.
And?
He was also a world champ when WWE was at its weakest point. With a depleted roster and WCW kicking it's tail every week. This guy was the ultimate opportunist, making the right friends, and associating himself with the best storylines.
In terms of his own actual ability, he's a below average performer who put himself in the right place at the right time. Take a look at the Kliq. Each and every one of those guys brought more to the table than HHH did, even a worse worker in Kevin Nash had more appeal in size, look, speaking ability, and creativity.
His in-ring work is among the most boring you will ever see and consider yourself lucky if you see him perform 4 actual moves during any match over the past decade.
I see this storyline for what it's is, another attempt to push Roman Reigns on everyone and to try once again to get him over at Wrestlemania. It bothers me more than they continue to force that on everyone than it does that a part-timer has the title. They gave it to the Rock just a few years ago and he was even more of a part-timer.
That said, I see HHH for the midcard in-ring talent that he's always been and give him credit for what he's doing in his executive role. He's doing a better job of that right now than Vince McMahon is.