This is a good point - in the space shuttle era, the SRBs were recovered, refurbished and re-flown. The boosters flown on Artemis 1 and 2 are now lost. There are only enough space shuttle era parts to fly another seven SLS rockets and the current plan to replace them with new hardware is still on-going.

I could not find out exactly why the SRBs of SLS are not worth recovering. If anyone knows why, that would be interesting to find out.