Imagine what people would have said if we got Garp, tsuru and sengoku running away from WB.
They wouldn't bring strategy as a reason to it, they would say how could Garp run and refuse to even give it a clash?
Yeah now apply this to WB, understand that he falls under the "Equal" to Roger category like Shiki, Gaban, Ray etc. I'd say Whitebeard as implied by Shiki and many others that he is a step above them tho. But, Shiki also implied Roger was a step above WB himself, and there are magazine, chapter 0 and Oda words in the bullet volume confirming that Roger has always been above Whitebeard at least him.
Roughly equal, that's it.
The true equals to Roger are Garp, Rocks and Harald imo.
How I see it:
Roger / Rocks / Garp / Harald
-
Whitebeard
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Ray
Gaban
Shiki
Sengoku etc.
Ray, Shiki etc are still a level that can be called "equal" to Roger, with Whitebeard being a step above being recognized as the strongest pirate after Roger's death.
Shanks is probably up there with Whitebeard, that step that makes him able to use kamusari when wings can't but that step below Roger because he factually sacrificed his potential when he lost his arm.