Metrication is the Path of Least Resistance
Metric is showing up in unexpected places. Major American sports broadcasters used to diligently convert most international sport events from metric to imperial. More and more broadcasters are just reporting results directly in metric without any unit conversions. It's possible broadcasters are making deliberate decisions to go metric based on careful analysis.
It's much more likely that the switch to metric for international sports is simply because it's less effort. Going metric is the path of least resistance, and this is a good thing. Actually, it is THE reason why the U.S. will eventually go full metric.
If NASA made a deliberate decision today to give a press release using metric units some misguided imperial zealots would lose their collective minds and go ballistic. However, NASA scientists being interviewed on podcasts will often naturally use metric units and the imperial zealots don't come after them with pitchforks. Likewise, when a private space company, such as SpaceX, makes videos for the public in metric it's hard for there to be any significant backlash because they are a private company. We see a similar effect in online shopping.
Consumer goods in the U.S. are mostly imported, and online retailers rarely do proper conversions to inch fractions for product information. Converting units takes effort. Retailers are lazy so they convert product information to decimal inches or sometimes don't even bother. Who are the imperial zealots going to complain to? Americans see metric everyday. It won't be long before NASA can give a press release in metric and nobody will have a psychological meltdown.
Australia and New Zealand did metrication correctly by switching all at once from the top down. Here in America we are going to do it the hard way from the botton up, but it will happen. Metric is more efficient and sensible than imperial, so it's ironic that metrication in America will be a side-effect of the world-wide race to the bottom.
Everything that can be converted gradually will get fully converted to metric over time.
Some metrication cannot be done gradually. For example, aviation elevation in feet cannot be gradually converted to meters because mixing up units would literally cause airplanes to crash into the ground. Even countries that are fully metric, still use feet for elevation in aviation. However, the more common metric becomes, the easier it will be to metricate challenging domains like aviation.