While this has devolved into a license and WoTC ethics debate, I’ll take a stab at answering the OP.
I am teetering on the fence whether to break my "no money for WotC" rule and getting the 2024 core book.
You have reasons to not buy the books. The only way I’d violate those reasons, if they were mine, would be out of necessity. Or, if I gave up caring about my reasons sometime in the future.
Let’s assume, at this time, you haven’t given up those reasons. So necessity.
- You run public games at your FLGS, conventions, or any Adventurers League opportunity you might come across. You’re probably gonna need to be up on the new stuff. That means PHB and maybe MM.
- You debate rules minutia, or even want to discuss rules interpretations online, you like talking about the art, you want to talk about whatever is in the books, what spells are doing these days, whatever, you’re gonna need them to reference.
Beyond that, don’t get them.
For me, the decision was, I don’t need anything in the new books to run my game. 5.24 is the same game as O5e. Same basic structure. I’ve already tuned up my home game with replacement rules we made up, 3rd party stuff, and ideas here and from the rest of the internet. The resources in the new books are VASTLY outstripped by the piles of stuff and imagination we’ve drawn on for new ways to have fun. The core books are there for the base structure, all the details, in my game, are flexible. Want to have a Ranger that does Y instead of X, hmm, doesn’t seem OP, so go for it, done.
The new core books are the new bog standard, I’d totally get them if I was starting new, and start deviating from there. But for us, our game is already way mor interesting and fun, not gonna reset to blander. Any mechanics improvements needed are already fixed better like when I found like 5 chase rule ideas to replace and we hashed out what would make the next one less stupid and work for us.
Apparently the monster manual is gonna be improved for mechanics, but I’m pretty confident it’s not gonna get to the gold standard for common monsters, the A5e MM, which is just so fantastic for running common monsters, plus there’s an internet full of other ideas. Only thing new MM could offer would be better mechanics for IP monsters, but honestly, the internet already has them beat, and all those MM Expanded books on DMs Guild have variants covered in spades.
The magic of DnD, or any TTRPG, to me, is all the stuff groups put into the framework provided. There’s lots of romanticization of the glory days of kids on bikes, playing in basements, making up stuff to cover what they didn’t understand or didn’t care for, we did it our way. I think those days are alive and well, but instead of just having your friend group and maybe a magazine to work from, you have the ideas of all humanity available. People all the time saying “I wish WoTC would fix…” Why, already 5 good fixes being debated on Reddit, pick one.
Unless you need to play by official for reasons outlined above, or are brand new, the new books are already obsolete IMHO. I you want to reset your game with some freshness and spit and polish on O5e but not give WoTC any money, there’s a few new takes out there with different core books to build from. About the only thing WoTC has going for them compared to others is a higher art budget.