I too share the enthusiasm for OLED. This is the single biggest advancement in panel quality on Notebooks ever - a much bigger step then the move from TN to IPS. However, we should be aware of the problems as well - the longevity has gotten better, but its still a weak point. Also, for OLED screens, you need coverglass - this is the reason why it was put on the X1 Yoga first, and only the X1 Yoga for this year. The X1 Yoga has a glossy OLED screen, hopefully we can have at least semi-matte OLED screens in the future.
I think if the X1 Yoga OLED is a success, Lenovo will start to put these panels in other models as well.
In the long term, I hope mLED can succeed OLED. mLED just seems like the perfect panel technology.
Maybe the first generation until manufacturers find a way how to cheapen the technology.
You say cheapen, but some of the things you criticize also are connected with high-res displays. Pentile matrix displays for example were developed to lower the power consumption on high-res displays.
Of course, IPS today is much cheaper to produce then it was 5 years ago, and it is much more common, even in cheaper machine.