I agree we should look at multiple possible paths for renewable energy, but to say that they shouldn’t work on this, is a bit far fetched.
This assumes the researchers working on fusion can work on the other renewable energies, when that’s typically not the case with highly specialized fields. Further, estimating the time it takes for advancement with the described time magnitude is a frivolous pursuit, if you put any weight behind it. Within 5 years, sure let’s predict. But at 30 years, now we’re talking a bit too far into the future. It’s much harder to guesstimate what will occur from now to then.
Lastly, if we assume it will take 30 years to produce a working model, then that only assumes we’re working on it today. If we could, let’s say, divert all scientists away from fusion research onto other renewables, the 30 year estimate would be perpetually pushed until we start working on it once more. Let’s have people who are passionate about their field pursue as many paths to solving the energy crisis as possible. We could have a breakthrough sooner than 30 years, which I would place money on.