Following the "trend" doesn't necessarily mean they will sell well. AFAIK the market is still >90% phones with 16:9 screens. I understand that a 2:1 screen (18:9, it's just maths) makes a big screen easier to use one handed, but it reduces usable screen in other areas, e.g. how many videos are filmed in 2:1 aspect ratio? Showing a 16:9 video on a 2:1 screen means that a significant part of the screen is not used and therefore wasted - a 16:9 video on a 5" 2:1 screen will be smaller than on a 5" 16:9 screen.
If HMD make a 2:1 screen phone I hope it sells well, but I'm not sure I'll buy one.