Hello Kathy, thanks for posting your information here - it's much appreciated, and sounds to be the most credible explanation. I also have found FS transcriptions a good way of filtering out the right record before purchasing the original on SP, and find it difficult to operate as effectively with just SP's indexes alone.
Ref some of the record still being on FS, there are only several thousand for each census year versus several million usually and, when I click on any of the entries that are there, I get a blank screen. Perhaps others can still access these.
With respect to census entries only showing individuals, only the day before these records started disappearing, I'd been working on FS transcripts for whole households. I'm not sure if this was a glitch before the pruning started, but I definitely had access to this. Even now, the indexes show other members in a household, even if you can't open the record to see the detail.
This all seems a shame to me. Personally, I was much more likely to purchase an original image from SP if I felt reasonably sure it would be the right one. Unless I can get the same confidence from running lengthy routines on SP, I'm unlikely to take the risk. Perhaps SP themselves might be working on a different form of index that encourages greater uptake.
P.S. FreeCen transcripts are still available at present.