The solids industry tends to be cyclical between big procurements for new ICBM's and SLBM's, and in between it makes DoD nervous if capabilities and institutional knowledge are lost.
Agree with the need. Not the history or manner to deal with this need.
However there are other solutions beyond burdening space launch systems with this cost. Suggest it was never an advantage for space launch but a lesser burden at the start, because the infrequency of launch and cost of other components/aspects of launch made it indistinguishable, especially when it was cheaper (some like Ed Kyle wish to hold on to the notion of expendable launch to the bitter end, from these origins). This grew into a long term dependence, and that "addiction" doomed many programs long term including Shuttle. EELV was originally to avoid this, but also is doomed by it long term. See no need to add to this toll.
(If Ed is right and reusable vehicles don't pan out, it is possible that solids can be made considerably cheaper as the next best thing to boost with, but in the industry I haven't found a single propulsion engineer to bet against reuse at 100:1 odds.)
Antares uses a solid US, and solids are used in space (Star series, even at one point SX offered it for payload assist). And so far only the boost phase has much demonstrated reuse (with the notable exception of Shuttle SSME ascent).
But the root issue is in how we budget weapons delivery development and contract bids - which is going off topic for this thread. Because we have to delve into the arsenal system, history, biases/choices, and rational resolution of irrational practices that got us here - which I'm not going to do in this post.
Bottom line - you don't wrap IR&D and sustainment into space launch as it wrecks both, you budget outright your weapons systems (like most other countries do). (Europe is learning this to the hard way now.) The history was wrong, it wasn't an American advantage, but a stupid cheap scam with a hidden backfire that burned us.
And ... from the standpoint of government bidding and acquisition, what I said upthread is exactly all that will happen. (Political forces can try and craft special funding to resurrect history not withstanding, but right now that won't be easy.)
And the roots of the problem aren't in the solids industry, but in the mediocre politics that surround the arsenal system funding.
Thank you SX snf BO for finally cutting the solids industry apart from its backward dependence, now it's up to policy makers to catch up with 40+ years of not properly funding solids because they found a way to avoid doing the work and getting it right from the start.