So far their rate of making these kits was very unimpressive, much like with JDAMs, the kit itself is far more expensive and complex to produce than the bomb, and even richest countries can't afford nearly as many as they have bombs.
Russians have used
JDAM style bombs like that since some time, but with smaller bombs mostly and without slap-on kits made separately, though the greater momentum of a bigger bomb lets it get enough gliding range that countering it with SAMs becomes very hard.
Even the kit based 1500kg variant itself is few years old, referencing 2019 as the time of development being finished:
www.globalsecurity.org
Zeihan is however wrong in saying Ukraine need a lot of aircraft to counter that. No, it doesn't need to shoot down everything before it gets into bombing range, it just needs to be able to inflict a decent rate of attrition on the aircraft doing it. And over long campaigns even seemingly low attrition can be surprisingly brutal.
Even losing humble 2% of bombers in each sortie, means that there won't be much left of the units doing the bombing in a couple months of daily sorties, extrapolate to the timescale of this war and very slow production rate of modern tactical jets...