Assuming I'm reading what
@MonsterEnvy wrote correctly, I don't think they're suggesting the 2014 books will be deleted from existence. They won't be printed again, you won't be able to buy them on DDB anymore, but if you toggle Legacy content on in DDB, you will still be able to read and use the books and associated character options so it wouldn't stop a player with those books to make a 2024 paladin with the 2014 half-elf rules. This is what they did with the books they retired when MotM was released, which
@Nikosandros said you can still share with new players through a campaign share if you have a subscription so it wouldn't prevent a table from saying "thanks, but we'll stick with the 2014 version".
This is all speculation at this point, but seems to be the direction they've been going so far.
Edit: Just checked and realized my DDB subscription isn't expired yet. I created a new campaign and enabled content sharing and sure enough Mordenkainen's Tome of Foes was available for me to share.
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