>>719688382
>I'm kind of intrigued at experiencing what captured millions for decades.

Other anon >>719697404 has explained it pretty well. With that said, Classic has introduced Hardcore servers which, in my experience, come the closest to what the game felt like in its Vanilla (2004) state

>the world is both mysterious and dangerous
>every upgrade matters: gold, professions, items
>people gravitate towards each other as numbers mean safety... most of the time
>people dying means there's a steady influx of players at all levelling ranges

The downside, and it can be a pretty big downside, is that in HC death is permanent and WoW was not thought as that kind of the game. It's filled to the brim with knowledge checks, some of which you'll realise quickly (if you enter a cave alone, you're already dead), others will be required 100 hours later.

Still, if dying and losing progress doesn't discourage you, it's honestly the closest you'll get to an actual Vanilla-like experience. You can even make an alt character to mail gold/items to, so that your next character has a headstart.

Oh and retail is irredeemably, obnoxiously, insultingly terrible, it's WoW in name only