I was looking through the Wikipdia article for Boeing aircraft and came across a concept known as the "7J7". It was supposed to allow Boeing to compete with the A320, as well as a successor to the 727.
"After Airbus launches the 150-seat A320, Boeing promises a radical new airliner with advanced propeller engines on its tail. The 7J7 will burn 50 percent less fuel, Boeing says, with a wider cabin, and it will be ready by 1992. Boeing flies the new General Electric engine on a 727 test bed, but the project is dead by 1987, killed by a combination of
lower fuel prices

(which make fuel savings less valuable) and technical risks. Meanwhile Airbus gets its first big U.S. airline sales with the A320."
MD had a similar idea with what they called the MD-94X.
"Configuration was similar to the MD-80, but advanced technologies such as canard noseplanes, laminar and turbulent boundary layer control, side-stick flight control (via fiber optics), and aluminum-lithium alloy construction were under consideration."
The GE-36 Unducted Fan engine looked like a torture device. (Actually, it strangely reminds me of the "Needler" from the X-Box game Halo)
It is somewhat ironic that the reason for this plane being cancelled was the gas prices going down, since it seems all they do today is go up. This may be one of the first planes I've heard of being cancelled for being too efficient for its time
😛
It is a longshot, but this maybe one way to save the MD-80. I personally believe Boeing should restart MD-80 production either with the GE-36 unducted fan engines, or what about using the GEnx engines that are being used on the 787? The new planes are great, but a updated MD-80, with new engines would be super efficient and would be just as durable and long-lasting as the original MD-80s.