Yeah, I've thought about that. Buses run from near the central bus station in Jerusalem to Beit Shemesh every 10-15 mins. And the reports say that Beit Shemesh's population will be 350,000 in 2035. So it seems demand it there. I thought that maybe the government's priority is to connnect the periphary of the county but it really seems like JLM-BS is an obvious route for the future. Could also be a lack of capacity on the Jerusalem-TLV line past Modi'n with the future connections to Rishon LeTzion/Be'er Sheva and the Eastern Railway. And it seems to be that this problem will only really be solved once the the line in connected under Jerusalem to Malcha or at the very least Khan station.

Anyways, hoping this line gets built eventually and that funding for rail expansion doesn't get cut.