To my mind it's not just about whether the teacher has time for supporting my kids, but whether they will get the best way in which to support them.
For example I was working on adding non equivalent fractions with my eldest DD9, who is either 2E or just really really average (jury is out!). When she tried to add the numerators together and the denominators together all I had to say to her was "Stop. SEE the 1/2, see the 1/4, now add them together." She then sat down and did a whole sheet of problems of increasing difficulty, including improper fractions with no difficulty. Her teacher would probably try to explain it to her. Which a) she's probably not able to listen to and make sense of and b) she didn't actually need a lesson.
DD5yrs is coming along quite well with her reading but I suspect at first her teacher was failing to identify that most problems she does have are due to letter and word reversals rather than decoding problems. When I am reading with her I tend to know which words she needs simply to be told the first letter, which words she needs help sounding out and which words she just needs to be given whole for now. So I know that her decoding is better than it may immediately seem to be. I am lucky that her teacher did actually listen to me after a few weeks that she was making the same % and the same type of errors 4-5 levels higher up than the teacher had her at and that reading easier books was not going to help her get past seeing "saw" as "was" or b/d and p/q problems. And that often she didn't need to be helped with words so much as refocused on the book or helped locate the first letter of a word if she was stuck. If the teacher had not listened we would have continued to have a lot of frustration between the two of us. The first few weeks I spent a lot of time trying to figure out if DD actually was less able at school (presumably due to anything but the work being more interesting). But this is certainly an area where teachers DO spend 1:1 time with children and yet for us there was a disconnect between the level my child was working at with me v. school (though it's now significantly more closely matched than it was).
