Not really, in fact what happened is exactly what was most realistic to happen.
He most likely btfo'd an admiral. Marines were like WTF, while Mihawk just kept going as usual. He didn't start occupying places, building up businesses or gathering subordinates. So why name him yonko? Instead WG made a bold move by trying to start a new project, The Shichibukai. Kinda ally yourself with people with balls that are not yonko cause they don't fulfill all criteria, so you can challenge the actual yonko with combined forces.
Fits perfect for Mihawk. He beat the marine's strongest force. There's nothing they can give him anymore, other than maybe some money and keeping other marines from annoying him.
Later, after the shichibukai project is cancelled, mihawk is considered an actual pirate. One week later, he supposedly joins some group that has exactly what he is lacking. Influence/territory, wealth, menpower. Even though they know their head is not on mihawk level, they name him yonko because you know why? Because it's Mihawk Mother fucking Dulacre we're talking about here