When I started playing L2 back in 2006, you could load as many accounts on a PC as you were able to run and pay monthly for. Even back then I was running 5 clients all the time. My archer main, my Prophet and a healer for solo exp and having two shops in town to sell the drops. Only until a few years ago, having 7 accounts online was not a problem. The servers went free to play, cheap and badly programmed bot programs (like the Tower one) reigned supreme and NCSoft took the easy way out; limit clients to 3 per pc, so only the very experienced bot train owners were able to run bots (they had to tools, means etc. to run game without the client and have one PC running 70-100 chars at a time).
With the auto hunt system clans are dying, party matching is dead and unless you have a solid constant party that is there every single day you won't play at all if they are offline. You cannot find a tank, healer, buffer or even solid (well geared, in right level range) DD. People have been using the auto hunt system and recent exp events to level up their characters so they can exp, because players being 110+ is what NCSoft wants us to be (all content coming to us the 16th of October is aimed at 110+, all content in January for 112+). But you cannot make 110+ on your own, or with a constant party unless you load all characters yourself. The game, with the last update, been designed and made for auto hunting and having a 3 client limit complete disables that.
I have not had a similar L2 experience as the to the one 13 years ago until they unlocked the client limit to 7 (and above) again. Able to log in characters at will, not having to log off an entire shop just to log in a buffer for something stupid like Tavern. The game was perfectly fine with everybody able to log their own party.