So spend $20 on Bluetooth headphones. There is a plethora of excellent BT headphones at very reasonable prices. For $80 you can get a pair of LG HBS-910 which are the most convenient, multi-purpose headphones on the market. It's 2016, I can't believe anyone tech savvy enough to be on this forum is still using wired headphones, that's ridiculous.
Besides, unless you're dissatisfied with the range of current bluetooth products (which beats the length of any headphone cord hands down) there's zero reason to wait for Bluetooth 5, since all it brings outside of extended range has to do with improved data throughput, beacons, and IoT stuff. You're making a mountain out of nothing.