We need to change what we call a 'Bitcoin'.
What you fail to realize is there is no "we". You will never convince every single user to start calling a satoshi a "Bitcoin". Names only have meaning if they are consistent. Imagine if at the same time there was more than one definition for a meter, it would be kinda useless to provide units in meters (which definition of meters). In centralized institutions the central body can proclaim a new change in value (like redefining a meter, or kilogram) but that doesn't work in a decentralized network.
I understand it. What you do not understand is how fatal the idea of a "coin" that costs hundreds or thousands of dollars is to the continued adoption of Bitcoin, a brand which leveraged the human tendency to ascribe value to collectibles beyond their mere utilitarian value, in order to to gain traction. That same leverage is needed to continue adoption, and fractional ownership does not push the same buttons in our ape brains.
Can you imagine would utterly confusing it would be if everyone you talked to had a different definition of what 1 BTC was?
Yes, but it is a much smaller problem than trying to convince people to collect .001 or .0001 Bitcoins by naming them something else. This is essentially a re-branding. It would just as hard as inventing a whole new coin, as far as public perception goes. And at least then you could make up less cumbersome names for units. I mean, 'Mil-E-Bit-Coin'? Come on...
A BTC is NEVER EVER going to change.
You sound like Bernanke talking about the Fed

To do so would require a consensus, it would require rewriting everything that has been written. It would still lead to confusion and chaos when people looked at outdated articles talking about (there will never be more than 21M BTC and the person own more than that himself). It simply is not going to happen.
If even a minority of existing users switch to the new labels, then the holdouts will be quickly overwhelmed by new users choosing the more intuitive language, assuming the adoption rate holds steady. The scale is so immensely different that context will easily show which system a communication is using. Do you really think someone is accidentally going to sell their private jet for a 10,000 Satoshis, because of a misunderstanding of folk names?
Most of the time you can't get 100 bitcoiners to agree on just about anything but somehow you are going to get millions of users to simultaneously change their definition of what a Bitcoin is? Really? That seems a viable solution to you?
It is a solution that tackles the core of the problem, unlike all of the others, which is that for an item to be consistent with the concept of a 'coin', ownership of multiples of the unit needs to be realistically attainable.