I don't think they're doing it on purpose. But they certainly are making organized raiding guilds obsolete with their stupid decisions as of late.
The whole M+ thing really grinds my gears because the best gear should come from raiding.
And let's not get started about personal loot. That decision alone make me quit being a GM/RL and I haven't raided in a serious raiding guild since.
So to answer your question, I don't think they're doing anything "intentionally" to kill mythic guilds, but I think they think they'll just survive (most wont).