It took 16 years from the first controlled nuclear chain reaction (1942) until the first commercially viable nuclear power plant was on line in 1958.
I would guestimate it will take that long to have a power plant producing fusion power. Add another 16 years to that, and I’d bet we have fully transformed society by 2055ish.
I joked, above (not entirely joking) but seriously, this is likely the most significant scientific success since the space program accomplishments. And actually, might be bigger than that.