With familyshare they do not earn money and do not get the sells numbers up. You buy one account and then you share this account with the whole family, even friends. Thats the reason why it is turned off on officials. I mean you can still do it, just another way, but thats another story.
Every account they sell is a potential player on the papers and this means reputation, free advertisment and additional money. 1 million sells or above and your game will get prices and recognition from big gaming magazines. They will hype you for free. People like to buy into games that get hyped because of high sellnumbers. Remember Vallheim? V-Rising, where sales got to the roof in a couple of days. Numbers are important. Constantly selling accounts is a must. Once numbers dry up and don´t raise anymore even after an big update, the games days are counted.
In all fairness, the pvp community may be toxic as hell, but with its constantly buying cheap alt accounts it is supporting Funcom in their own way. Accounts are cheap and the playercount doesn´t go up ingame but yet it does count on the papers.
Another side of the story is, that it would simply be impossible for Funcom to handle all the reports and bans on alt accounts. First they would have to proof that you are the same person with that alt account, which is highly unlikely, because several people in a building can share the same public ip adress if they are sharing the same router. If you turn your router off and on again, you most likely will get another public Ip adress. Most European countries are very strict when it comes to datamining and datasharing. They have laws of what data can be shared and most of them require you to consent. Without your consent only limited data can be shared. Probably the IP adress would be without consent, I don´t know, but still you would have to proof its you using this alt accounts and internet providers here need to cut of your internet connection every 24 hours for a second so you are regularly changing IP adress. You can also use cheap vpn. So in order to ban you for god they would need to ban your direct pc id, which they can´t expect you are using real cheating software and they can proof that your actions have caused them financial loose or hurted the company in another way.
Even if Funcom would forbidd to use alt accounts its like I said before. People do not care about rules on officials. They come and go as they please and they play the way they wanna play. It is what it is and its not changing, no matter how we think about it privately. This is a battle between the pvp players and Funcom that started years ago. Funcom never got the upper hand and they never will. But they learned to use some stuff to their advantage and that is all their is to it. Funcom makes a move, the pvp players make one. Its a constant back and forth battle and they will never be on the same side of the page.