hohlraums are not expensive because of base materials, but because today we generally produce them as one offs and the process is incredibly man hour intensive. The DOE "roundtable" on the announcement today addressed this.
They are one-offs, but even if they were to be mass-produced, they require extraordinary precision. I very much doubt claims that one can be built in the range of a few dollars that each shot is worth in terms of generated electricity.
The reports you quote actually mention the target costs very clearly. The IAEA one talks about needing 500,000 targets per day, and sets a target of 0.30$ per target. At the time it was written, it says that a target costs 1000$, which is probably before NIF found put just how much more stringent the requirements for the shape of the target were (since the numbers I saw last time NIF achieved ignition were closer to hundreds of thousands of dollars per target, though maybe I am misrembering).
It's also worth noting that that report was expecting NIF to achieve the current milestone within 3-6 years, and it actually took 13. So I feel their numbers can well be considered optimistic.
For an actual look at the challenge of ICF i'd say look here: https://www-pub.iaea.org/MTCD/Publications/PDF/TE_1704_web.p...
and also consider that it might be used in combination with MCF for example: https://medium.com/fusion-energy-league/the-fundamental-para...