- another aspect you need to look at is the attitude of folder makers
Sure, there are some who are happy to plod along producing what they've been making for years - then there's others who like to look forward and innovate.......ideas, designs, materials etc., they all evolve.
Some of this new ways of making will include bearings - so a maker may see what others have done and try bearings instead of bushes, particularly so if they see that they're catching on and selling like hot cakes. Also, they may wish to try for themselves anyway.
Am not going to say for or against, but I can see desire, the benefit of both types of blade opening...