There are any numbers of reasons why some people may prefer to wait for the 2018 phones.
Here are some of mine...see any of these coincide with yours.
1. The ipX is a liitle too large even with the reduced bezels.
2. I want OLED for my next phone.
3. There's a lot of questions surrounding FaceID. I'm not willing to give up the convenience of TouchID just yet.
4. Buying an ip8 when I already have a 6s is counter-intuitive.
I would be be giving up the convenience of the 3.5mm jack and being able to listen to music while I charge the phone (I do this nearly every day).
Add to this that the 128gb model is now gone. So I'd have to shell out $850 (for a 256gb ip8) to replace my 128gb 6s.
That is a huge amount of money for wireless charging, stereo speakers, and upgraded CPU and cameras.
Finally, when you throw in that the ip8 is the same basic design as the previous 3 iPhones (albeit now with a glass back)...I'm not enthused about buying it.
I could add to this list, but I think you get the idea...I will buy a new iPhone when Apple does something worth the cost of what they are charging for it.
Work harder Apple.
The ipX doesn't do a thing for me and the features you offer in the ip8 aren't enough for me to upgrade.