why no lcr in .22 mag?

[carguychris]

is this the s&w .22 mag you talking about: (link to S&W M351C SKU# 103351)

I believe the prior posts referred mostly to the Model 351PD, SKU# 160228, which features an external hammer, the ILS, and a Hi-Viz front sight. AFAIK #103351 was a distributor exclusive from a couple of years ago.

it seems very unpopular and expensive.

It's arguably both, but S&W has cataloged it for years, so it evidently serves a market segment large enough to justify continuous production.