Going off of Thomas's ratings list, interesting that a few shows had fair ratings, and still only ran for a year or two. Case in point, Marble Machine and High Rollers were doing better than Wheel, but were gone in 1976. Jackpot did slightly better, and was gone within a few months.
Thomas pointed out these were season to date ratings through July 13, 1975.
Magnificent Marble Machine premiered July 7 (per
http://www.curtalliaume.com/gameshow.html), so only five shows' worth of ratings are included. (This is one of the reasons why I take the argument that the 1976 version of
Break the Bank was inexplicably cancelled despite rating third for the year with a grain of salt -
EoTVGS' ratings list ran through late April, which meant only the show's first two weeks' worth of ratings was included. I'm pretty sure that if the show's rating remained that high throughout its run, ABC would have found a spot for it elsewhere.)
I don't think the 10 AM and 10:30 AM network shows did particularly well.
Celebrity Sweepstakes and
Spin-Off are the two-lowest rated shows on the list, and
Wheel of Fortune and
Gambit (which both aired at 10:30 at the time) are pretty low as well. (
The Price Is Right was still at 3:00 PM at that point.) Still, the combination of the latter two had 65 percent of the TV viewers at 10:30 whereas the former combination garnered only 52 percent at 10 AM - it's possible there were lots of stations dropping the 10 AM shows for a movie or a 90-minute version of Mike, Merv, or Dinah.