I knew this is gonna be a spicy thread, but still...
None of these policies are official or anywhere written. The original design was prone to fail a little too easily, yes. Many of us were told that it can be brought in, exchanged, and some even heard about a 5 year window for this. This surely could be an internal policy that was told to many clients by the SAs, but that is nowhere near official. They don't have a Service website with all the Recall Programs like what Apple has (whose programs also end after a few years, and individual clients are never notified, they have to find out themselves). And even if they had this internal policy for a few years, ALL free repairs and exchanges were and are at the discretion of the Repair Specialist. They could follow this guideline if they choose to. I can imagine there were many bags so beaten up that they didn't offer free exchanges for. But there never was a PDF on louisvuitton.com saying anything about such a legally binding program or a 5-year extra warranty.
The bag was redesigned. It is highly likely that is was because of the fragile nature of the original, but Vuitton never ever officially stated so. We just assume. They redesigned the Speedy like 3 times since 2000, none of them was because Speedies were falling apart left and right. So this argument is also not valid.
I am not defending them for making a poor product, but they have 0 legal obligation to do anything after purchase. Their watches have 2 years of warranty, nothing else has any. After we leave the cash register, any of the "free" services are just gifts. They don't have to do them. The marketing about their quality (which is still true in most cases, like 99% of the time) is also not legally binding.
And my experience, if a client has a good relationship with the store and/or comes in with issues like this being very friendly and kind, the SAs tend to be very kind and helpful, and paid services can get cheaper or free, even if there is no magic policy for that bag.
This was an unpleasant experience, I understand that. If you try again (and maybe again), as others recommended, the response might be different, but this is a delicate game with their representatives.
And despite some shortcomings, their Repair Department is still unparalleled. No other brands offer such extensive services. Saying it as someone who was denied repair because of cracked canvas. These are their rules, I understood and moved on. Other times, they replaced handles for me for free, even though I didn't even ask for that.