Why wouldn't more data be better? If you used only the last couple years the trend would probably say Bitcoin is going to zero. That doesn't seem very useful.

What I found most compelling is that the trend line with data only up to 2016 is still almost the same as with all data. That's 7 years of data with 2 bulls and 2 bear markets not included and we're still within that range.

Obviously we can't predict the future, and I called that part hopium for a reason, but I can't help but get excited at these things.