So, Shiro is stepping-up to be "all that he can be" and if we follow BACK TO THE FUTURE logic, the change in how and WHEN Shiro takes control of his powers should be enough to invalidate the Archer concept as the past he experienced no longer can exist. Shiro is now aware of the mistakes ahead of him and is almost honor bound to find other ways now. Not to mention that if these events had already happened, the Hero Shiro/Archer would already have known that he was going to fail...
Nasty bit of work that grail though... I don't think that I would fight to obtain it... I'd fight to be RID of it! Yuck!!!
Now for Ken's OPINION Corner. You are free to disagree, but it will be your opinion as well, so neither of us is "wrong" until someone can time-warp a classic "National treasure" quality sword in from WHEN IT WAS NEW to test against a $3500 + dollar Hanwei special-commission and be willing to destroy them both with blade-on-blade strikes. (The Japanese Government would call for your extradition for a "Proper" beheading if you destroyed something that historically-significant to Japanese culture!) I would NEVER risk mine!
Funy thing about all this griping by Gilgamesh about "fakes"... Outside of science fiction, a modern-day high carbon blade made to emulate a WW II Fine Japanese sword would snap the original if all things were considered equal. The originals WERE very sharp, but not very resilient to side-strikes and were prone to snapping. (NOT shattering like they do in animes & hollywood movies!) A modern-day sword could be sharpened as keenly, but would be much more durable/flexible. Would I put an eBay $400 sword against a Jspanese WW II classic? NO WAY! But a quality Hanwei or even Cold Steel would be a capable match, and a custom work would likely hold up well and even hold it's edge better.