Huh, I don't understand. If it's so easy why don't they do it? Oh the "value of store" goalpost pivot. Right!
Let me add some reality checks here. Irrespective of the fees problem - I know Segwit, Lightning network etc will solve everything, the real reason they don't is because Bitcoin/cryptocurrency is difficult for people to understand and use.
Most of the discussions about bitcoin et. al forget at the end of the day your system should be able to cater to a layperson. Currently, looking at Bitcoin discussions reminds me of this scene from Silicon Valley TV series: