[alumnox]

Originally Posted by Cherry_Lover

No, it wasn't. The two things you posted have absolutely nothing to do with the timing of the next Grail War.

Last page, epilogue Five years later right from the Fate zero novel.

Spoiler for FZ:

Kiritsugu pretended to gaze out towards the distant moon, and hid the sorrowful memories with a bitter smile.
“Hmm, it is rather regrettable. Heroes have a time limit too, and it’s hard to fulfill once you become an adult. It would have been better if I realized that earlier.”
Had he realized it earlier – then he wouldn’t have been tricked by the sweet lie of miracles that flew the banner called wishes.
Kiritsugu had once released a demon powerful enough to destroy the world because of his aspirations. It was too late when he finally realized his mistake. Countless people had died because of it, including Shirō’s own father and mother.
And that harbinger of Hell was still lurking beneath Mount Enzō even now. After that battle, Kiritsugu had repeatedly visited that place with dynamite, and spent years to map out the situation of a few leylines. He had meticulously created a ‘bump’ at a location leading towards Mount Enzō. That might be the last time for him to use magecraft in his life.
The prana produced from the junction of numerous leylines will collect upon that ‘bump’ with time. When its limit is reached, a localized earthquake will be triggered deep within Mount Enzō.
If all his calculations were correct, then the cavern within Mount Enzō would collapse and seal away the “Greater Grail” forever. Though he would not be able to live to see that day, Kiritsugu had done the best he could to prevent the fifth Heaven’s Feel 60 years later.

Kiritsugu playing with the leylines of the underground system is what messes things up.

Originally Posted by Klashikari

Spoiler for .:

That doesn't even count as evidence whatsoever.
First and foremost: the VN insist on -destroyed- grail (which is, as cherry lover already explained, the lesser holy grail, not the Great Grail).
Purify would mean its truest sense: the grail would have been no longer tainted and be just a pure prana artifact, which would be the appropriate wish granting machine.
Thus the question: if Shirou "really" purified it, why would he destroy it afterwards? Why would Waver and Rin go as far as dealing with the -greater holy grail- later?

The lesser grail is just a catalyst that was accumulating the Heroic Spirits in order to allow itself to materialize fully, in order to open wide the connection with the Greater Grail which is below the Mount Enzou

Spoiler for End of Fate Zero:

(it is even more explicitely explained in Zero than SN, as the epilogue describes Kiritsugu's plan in dealing with it, with the explosive which would detonate within 30-40 years after the 4th Grail War).

This is the very reason why the Mud was still sipping out, which generated that incident at Fuyuki. This is also the reason why Illiya had to shut the door herself in Heaven's Feel.

Ehmmm you are aware that what happens in the 3 routes of Fate stay night are not consecutive right ? They are 3 different possible endings to a unique stream line of events.