For anyone actually concerned about backwards compatibility, Crawford has basically said that as long as you read the 2024 book, and do exactly what it says, in a robotic fashion (my addition), then it will work. If you take the 2024 wizard and beep bop boop read it exactly as it says with no second guessing and then take the 2014 necromancer and beeop bop booep read it exactly as written... then everything will be fine.
The general consensus among people who have actually seen the book, is that for any DM who has even altered the HP of a monster statblock before, adjusting 99% of the material is simple, easy, and obviously straightforward.
As for the pointless debate about the name, though I am sure this will do nothing to shift the gnashing of teeth, I am going to put this up.
There is NO possible way to get confused here on Amazon. DnD Beyond will be equally clear.
"But, what about those poor souls who wander lost and confused into a gaming store?"
Yeah... those places that have employees who are knowledgeable about their products? Who likely answer questions every day, all day, about the things people are buying? Who likely are going to have massive promotional posters everywhere? Yep, those people have no hope. There is absolutely no possible way they could figure any of this out. I'd even bet there is nothing that could even give them pause to wonder if something might be different about the 5e rules they've been playing for years
Nope, we may only lament these poor, lost, confused souls who have no conception of the fate that awaits them, which is sure to be fierce and terrible, and in no way easily solvable by speaking to someone or reading the preface for the Book, which every WoTC PHB has had, which likely references the anniversary and the 10 years since 5th edition started.
Utterly hopeless I declare it thus!