I would not say that you have to hear so many components if you can tell when it is right. You need to be VERY familiar with live music and not just from the mid-hall perspective...most recordings are not made that way and the sound is far closer to the upfront and present sound of sitting very close to a performer. If you can hold that aural memory well enough then you can judge closer to lifelike (it will never sound absolutely live...the recording itself prevents this) or further...no need for a number scale.
I was giving a simplistic explanation of an example using a numbered scale to show that some components are more live like than others (and some will be negative). If someone is not an audiophile, he can suspend disbelief with very average gear. So really to know which is more live like than the other and which fits into the constraints of one's budget and space one has to hear many. Many components and many systems with different strategies to see what works best. Otherwise you can buy just about anything and satisfy yourself