I never said it was the only thing responsible in the rise. I'm just saying it played a role.
Obviously he was also hunting devil fruits, but as far as we know he doesn't have a third devil fruit yet, and few weeks ago, he was on Amazon Lily, but didn't gain any additional devil fruit, so whatever hunting he had been doing was more than likely related to his crew, not himself, which indirectly played a role in increase his threat level as the captain of the Blackbeard pirates, but certainly not as big a worth as what he gained after the invasion of WCI
That invasion potentially allowed him not only to indirectly crush the remnants of an emperor crew, but gain 2 important keys(Poneglyph + Pudding capable to read them) to get closer to Laugh Tale