I think a lot depends on the age of the student and their objectives. If this is a youngish person hoping to make it as a CPL/ATPL then they probably aren't going to make it.
If it's an older person who wants to fly VFR for fun and they can afford it, then perhaps objectives need to be set every ten hours or so.
About forty years ago I did my first solo in the UK after some 7 hours instruction taken over about six days (RAF Flying Scholarship, thanks chaps, not a rich Daddy). But that was on top of a bit of earlier dual time in Chippies and a week gliding at RAF Swanton Morley. However, If I was starting out from scratch today, I bet it would take me a lot longer than 7 hours to go solo.