Cultural and attitude changes can happen and can be swift once a tipping point is reached. Let's find small areas where we can tip the country over toward metric, and then build on that success. This is probably easiest in medical, technical, engineering, trade, and government arenas to start with, but any progress would help shift public attitudes and expectations.

There is quite a bit of metric in use already - engineering in electronics, automotive, machinery, etc. may well be done in metric, even if the results are presented another way sometimes. Scientific and medical research of course are metric.

The key to making progress on switching the country lies in finding areas in which we can build consensus that metric is the standard and must be expected. For example:

• The American Academy of Pediatrics and many other groups are insisting that "milliliter-based dosing should be used exclusively when prescribing and administering liquid medications." [link] When 70,000 children go to the emergency room each year due to medication overdoses, we can insist that it is unacceptable to give dosing instructions using teaspoons. That's an easy one - and one small way that metric units should become more entrenched and gain exposure to the public.
• We should not start with trying to get everyone to agree to change their weather apps to use Celsius (that would be a longer-term goal), but maybe we can build some consensus that we can stop using "inches of mercury" for air pressure, and standardize on millibars or hPa (hectopascals).
• Surely people can agree that millimeters are a natural choice for talking about small distance measurements, and we can talk less about strange inch fractions. Perhaps we can build on that to introduce more metric-sized fasteners (bolts, nuts, screws, wrenches), since metric already has inroads there.

Unfortunately, there is a cultural perception that we just don't do metric in the USA, and it's something to be proud of. We need to break that paradigm, show that metric is indispensable to our nation and economy even if it is not always very visible, and build the mindset that it is not "foreign" but something to be expected, at very least in certain settings.