It might not be that the Ascians are making us stronger, but that they are pushing the beat tribes to summon their primals with more power, hence the HM and EX versions. We are getting stronger as a result, we HAVE to get stronger to face the power of the primals. What does this have to do with anything? The Primals being summond disrupts the flow of aether, which is basically the lifestream of Hydaelyn (The World). The more crystals used to summon the Primals the stronger they are and the larger the effect the summoning has on the aether, which may be what is weakeneing Hydaelyn (The Mothercrystal) allowing her to be corrupted. What Lahabrea might have meant when he said he is doing everything he can is keeping the beast tribes focused on their tasks and perhaps teaching them how to summon stronger versions of their Primals.