I think there's a growing sentiment that we need to be decarbonizing our economy right now. We don't need any new technology necessarily (though some technological advances might make it cheaper and/or easier), we just need the will to do it.
In that context, betting on hydrogen is a way of smashing the snooze bar: the technology isn't quite ready, so we'll do some research projects and so on, and maybe we'll have something ready as a mainstream product in a few years, or perhaps a decade.
Same thing with nuclear fusion. I'm all for fusion if it pans out, but we should treat it as something that will make decarbonization a lot easier if it works, but in the mean time we should plan as if we don't expect it to save our bacon. There's an idea that "if climate change is a problem, some currently non-existent technology will save us so we don't need to change what we're doing now." That's what many of the climate-aware public are reacting against.
Hydrogen has some additional problems as well: almost all hydrogen comes from cracking natural gas, so it's effectively a fossil fuel. Green hydrogen is a thing, but it's not very energy efficient to use electricity to make hydrogen from water, and get the energy back by turning it back into water. Lithium ion batteries are in the high 90's percentage in terms of energy out/energy in. Hydrogen is, what, about 60% or so? Or maybe less? That's a lot of lost energy, so anywhere there's a viable alternative that doesn't waste huge amounts of energy we should use that.
As far as storing months worth of grid power: that's a really hard problem but I'm not convinced it's one that we even need to solve. Perhaps we need grid storage more on the scale of 12 or 24 hours to buffer solar variability. For seasonal variability we need better grid interconnection, including long distance HVDC lines to enable buying and selling electricity across time zones and perhaps even between the northern and southern hemisphere if that's what's needed. Keeping fossil fuel plants online as an emergency backup to be used in rare circumstances is also an option, we just have to make sure the rest of the system is able to handle the load the vast majority of the time.