They are, but one cannot simply overcome them by replacing the CPU. You have to buy new laptop, which is why performance is taken into consideration when evaluating laptop models.
On a personal note, can't wait to switch off of my 2015 MBP 15', even though I agree with touchbar & touchpad size scepticism.
I am decoding 4K HEVC just fine here, although at a low 5-10Mbps Bitrate with CPU going to 70%.