That's not idle speculation, either: Show co-creator David Crane admitted as much in an interview with RadioTimes.com.
As Crane explained, they weren't sure whom to ultimately pair Phoebe with — scientist David, or pianist Mike. The triangle was part of the final two seasons of the show, where we saw Phoebe dump Mike, when he refused to commit, and return to David. But then Mike proposed and ... well, that sealed the deal.
But she might have stayed with David!
"There was definitely a possibility of that," said Crane. "I mean, we didn't definitively know (whom she'd end up with). They're both amazing actors. I mean, both Paul and Hank are fantastic, and fantastic with her. We sort of went back and forth."
He continued, "I don't even remember all the pieces that led to where we landed, but yeah, it could have gone the other way. Phoebe would have been great with either one."
Mike and Phoebe wed in the 10th season episode "The One With Phoebe's Wedding."
David had proposed, too, but Phoebe rejected him in the ninth season's "The One In Barbados, Part 1."
We like to imagine he's back in Minsk, having created a shrine around the statue he thought was of Phoebe. That's a happy ending in itself.