I'm not sure about the entry level models specifically, but ARC have removed sku's for the REF10 phono and preamps and others I forget. A dealer I spoke with earlier this week said ARC have only 7-8 sku's now because parts have become unavailable.
Why was the entry level line at Audio Research eliminated?
One of my first tube preamps was the SP-16. I believe it was the last preamp that founder William Z. Johnson developed. Price was around 2K-2.5K w/phono. It was an excellent reliable preamp. But now if you want a new entry level ARC it's not available. Too bad. Was it just not profitable. It was an excellent way to get into their gear and move up the ladder over time.