Firstly I wanted to say i think most of the account sales which is not supported by riot is due to the fact that it is really hard to level an account from lvl 1 to 30.
I myself have two accounts at lvl 30 and a third one up and coming and most of the times I have contemplated buying account just that it takes forever to level up your account. Also i know a couple of friends of mine that recently picked up this game but not long after quit as it was taking fairly long to level.
I know there is like a beginner, amateur and expert selection when you create and account but i dnt know what the significance of that is. Basically I want to propose a couple of things.
Firstly i would like to propose some incentive, i mean yes you get those cool banner for great leader, honorable opponent and Teamwork but they only provide support for people to abide by the summoner code. They are not in any way helping to improve the game play for people new to the game to get better (you can have nicest and friendliest people in the world but that doesnt mean your going to win your game, they need improvement in skill). Same goes for the ip boost, i mean really come on, everyone knows that you dnt buy runes till you unlock the tier 3 runes and when you have free week champions who needs to buy champions.
I couple of things i would like to propose are firstly the xp boost, as much as i know how much riot wants to make profits i mean come one your pretty much saying here you are bad buy xp boost so you level quicker and reach 30 to play rank and be bronze 5 forever (not always the case but most of the time its true) wouldnt it be better to get them to level 30 than let them buy skins for champions which cost more than what xp boosts do.
Personally i believe they should make xp boost a milestone or set them for after a certain wins. So for example if i was playing on a low level account and I just won 10 games in a row right, than a message comes up well done summoner your on a massive win streak and for having a perfect match history you will now receive a 4 game xp boost. The reward of xp boost was due to me performing and putting an effort into not loosing any of my games that gives the summoner incentive to keep doing well as if you win your xp received from the boost will be greater than if you lose. After the xp boost is used up the counter goes back to zero and than they have to win 10 games in a row to get the next 4 game boost. Now you can not always win 10 games in a row so people will try to perform and improve their skills to level up quicker (also only for normal games not bot games). For people just playing for fun they would not care about these boost and play the game as they like but for people who want to level up they will play better to get these boosts.
This will than say to the people for all you already lvl 30 people out there as well as new comers you dnt need to buy accounts cause its easier to level up low level accounts now due to the xp boost at after certain win streaks. As riot is against account sales this might be a way to help them around it. I mean it takes 3 months for an average person to lvel an account from 1 to 30 and do you want majority of your summoners to be below lvl 30. this could also mean they would increase the ranked community as more and more people will be reaching lvl 30 so the number of people on the server would increase. Meaning i will not have to contemplate buying a level 30 account as I would able to level my own lower level accounts.
Lastly why do i have more than 1 account well sometimes when your on a massive lose streak you tend to want to play on a different account sorta like a fresh start. It helps you play better as no one knows how badly you performed or you just put it behind you and play the best you can. I jump accounts when im doing bad and i tend to do good on the account and come back to do good on the original account. I dnt know if that helps you understand.