Selling accounts is now stupid - although allowed officially, seller, buyer, the account to be sold will be tagged when caught. And it's a good step forward, since the reasons for such a deal can be at least shady, if not plain scam.
Plus now the merit system makes leveling up difficult for spammers, so the way the worth was calculated in 2013-2015 (I don't know the exact years) is different from what it would mean now.
Sometimes, let us assume, for example, a high-ranking member who has been banned for any reason or wants to increase his profits by having more than one account. Instead of waiting 8 months, he will buy an account and will not face a problem in ranking.
Also, spammers know that it is impossible for them to rank-up, so buying an account and participating in bounty campaigns is a good option.
Good... maybe as business. Apart of that is still shady. Background and writing style is changing. It's not the same person. Even more, it's ban evasion.
And maybe in a day or a year the deal is caught and the account tagged. If it took long enough, maybe there is ROI, but it's not guaranteed. The risk is very high.
Spammers... they may be fooling themselves that nobody would notice a smart and useful member, instead of improving over time, suddenly becomes spammer.
How long until the account is tagged and it's value drops to irrelevance?
So no, sorry; I stand to my initial conclusion: it's stupid and shady.