It looks like COVID took his attention
Mike Bloomberg Promised to Spend Big Against Trump. What Happened?
He gave $331 million to support NY's contact tracing project.
My SO saw something a few weeks ago that Bloomberg has promised at least one of the groups like the Lincoln Project a blank check for the general election. At the moment the PACs of ex-Republicans out to unseat Trump have plenty of money for what they are doing. Rick Wilson said a few weeks ago that what they had done thus far was just warm up pitches and at the level they are operating combined with their influx of money, they have plenty on hand. But they plan to saturate media in the closing stretch of the election and they will need a lot of money for that. That's probably where Bloomberg will chip in.
The last few election cycles have shown that a blizzard of money doesn't do the job anymore. Hillary spent significantly more than Trump in 2016 and lost. Bloomberg and Tom Styers both spent staggering amounts of money on their campaigns and only netted a handful of delegates.
The landscape of campaigns has changed. It's now staggeringly cheap to create political ads. A couple from Portland has been making ads on their home computer and putting them on YouTube. I think one of the ex-GOP run PACs hired them. Rick Wilson said that the ads they are making to taunt Trump cost them about $5000 each from making them to getting them on Fox News in the DC area. And then they get millions of views on YouTube. They may actually be making money off of that.
Over the last 25 years the landscape of television has become increasingly balkanized. Back in the 80s and most of the 90s most people watched network TV, so ads could target large audiences at once. Now viewership of network TV is way down (I saw an article a few years ago that when the original Star Trek was on, it was in 3rd place for it's time spot with viewership numbers larger than the Big Bang Theory which has been the most viewed network program in recent years). And most people have ways to defeat commercials so they don't watch them.
It's more complex to get views of an ad like targeting people on Facebook, but ultimately that ends up getting the ad you want in front of the people you want only for significantly less money than a TV ad. In 2016 the Russians were taking advantage of this targeting liberals with one set of ads and conservatives with another set.
The Republicans have resisted every effort to get high speed internet to rural areas because their tried and true method of running ads on satellite TV will be derailed. They have an audience watching their propaganda channel (paying them to watch GOP advertising) and they won't go anywhere else. If they go online for their news, they will be targeted by people trying to change their minds.
People are also very polarized these days. Some of this is probably due to the way people are consuming their news, but it is probably some other factors too. When people are very polarized, their minds can't be changed with any advertising. So political money has less impact than it once did. It doesn't stop politicians from raising mountains of it and spending it though.