Steyer and Yang do not resonate because they have no political experience.
Bloomberg was mayor of a city that contains almost 3% of the US population.
In fact, 38 states have fewer people than just the city of New York. https://spoilednyc.com/map-of-all-the-states-with-smaller-population-than-new-york-city/
So, don't kid yourself into thinking that any billionaire could do this. To many voters, experience matters. Whether it be Pete (mayor of a college town with about 100,000 residents) or the aforementioned Steyer and Yang -- there are steps towards becoming the president which usually involve being in congress (rep or senator) or a governor.
Billionaires have been the power behind the throne for many years (just look at the Senate and who is bought and paid for by the Koch brothers and how they voted on impeachment). The only way that they can be the front man is if (a) they want to take the heat and (b) they are willing to work incrementally up.
Let's remember that it was REAL BILLIONAIRES who funded the Trump campaign -- those within the US to get that sweet tax cut and those without at the behest of Putin, Saudi Arabia, UAE, etc to either control US policy or weaken the US and the west. He was a useful front man.
So, I wouldn't read too much into Bloomberg -- except he appears willing to spend a boatload of money to counteract Murdoch, Koch, and friends to try to get enough 'did not vote for President' or 'wasted vote on 3rd party candidate' to vote for whoever has (D) next to their name -- hopefully all the way down the federal level of the ballot, at least.