I think they are to blame. Qualcomm is one of the biggest (if not THE biggest) manufacturer of ARM chips, yet they still simply use reference designs. Besides, for the next flagship (Snapdragon 888) they switched to Samsung 5nm (inferior to TSMC 5nm) and they're not even using the ARM-recommended 8MB L3 cache, but staying with 4MB.

It seems benchmarks for tha SoC aren't bad, but it really shows that they aren't really trying to catch up to Apple.

(My source is https://www.anandtech.com/show/16271/qualcomm-snapdragon-888...)