Has Golovkin now lost the power to even hurt a fly?

Where has his mythical punching power gone since he fought Kell Brook? It's like his body has become so weak, to the point of looking like an old granddad. The power in his punches look like they couldn't even hurt a fly and contain the power of a feather making contact with a solid object. Or is it his stiff, robotic and mechanical style causing injuries to his body due to a lack of flexibility? I don't think I've ever seen too many boxers who are as rigid and inflexible as Gennady Stiff-Lovkin. It seems like at any given moment now, his fragile looking body would break down if he tries too hard in punching. Which is exactly the signs he gave when he fought Daniel Jacobs and Canelo Alvarez. Or are elite boxers too much for Golovkin to handle and his power is only relevant against taxi drivers / shop keepers / restaurant owners / police officers?