Asking to get paid in Bitcoin is already a stiff barrier to entry for most users, so probably not. $300 feels close to the upper threshold where people who already care enough to not balk at the Bitcoin requirement also won't balk at the sticker price.

Ahh, yeah you're totally right, I keep forgetting that the victims need to pay with bitcoin.

Well. I guess it's good that there's not a more convenient way to give in to the criminals' demands!

They passed up a good opportunity for price discovery: have the ransomware pick a random number between, say, 10 and 1000 and learn from that for future attacks.

Other ramsomware authors did this. I remember reading that the optimal​ amount is somewhere between 300 and 500$, but i can't find a source anymore.

They could also make a machine learning model to take into account the part of the world, the hardware model, and other wealth indicators.

They probably would have made more by being quiet about the infection and renting it out as a botnet, or selling whatever interesting data they found.