I have heard this from almost all hi-fi equipment dealers that speakers make the most of the difference, spend 75% on speakers etc.. Only one from Overture, DE said it is 50% speakers and 50% equipment that I agree.
I used Plk, JBL, Infinity speakers so far with Denon, HK and Yamaha revivers. Then 2 years ago I got Focal Aria 926 that are high end to me.. and started playing with Marantz 6014 and Denon X4300H.. Everything should have been fine, I should have heard as I heard in the store.. right? Answer - Big NO..
This was all until I got Rotel and ADCOM amps, latter taking tt top notch to the quality and probably even better than what I head at the store!
So need dedicated amps for Full size big tall Floor Standing speakers and then changing speakers will give you that benefit
If using receivers, better stick to book shelf and satellites!
And am deliberately leaving sub woofers out of this discussion! 😊