It’s in no way a matter of cabling and tweak products such as vibration absorbers, contrary to what the either delusional or perfidious dealer suggested here. Yeesh…talk about misleading.
The primary factor is how much space you allow between the speakers and room boundaries. Additionally, bass smoothness, proper room treatment for ideal decay time, the phase of the recording, and overall speaker performance also play critical roles. All the rest affect perceived depth by far smaller margins.
I’ve setup systems that can create incredible depth for relatively little money, so it’s not so much about how much you can spend, but high quality speakers are a must.