Hahaha that’s too much money to spend for changing one’s username on a online forum. You quoted a post from 2014, the price of 50bitcoins then and now are not the same. OP wouldn’t even consider such an expensive option.
Yes it is from 2014 I tried to search and I ended up at
donation page it seems they changed it and they are no longer accepting donations. So there's no hope of becoming a VIP member for changing the username. His last hope if theymos and cyrus will grant his request.
@OP why not register the Username that you want if your problem is the limitation you can buy the
Copper membership to increase the limitation it is cheaper around 40k sats.