The issue is that years are not being frozen. Kids are still progressing up each year but will have missed chunks of the curriculum out. For some it is the building blocks, for others it is more advanced. This years A level students for example will go through knowing less than any other previous years students. That puts them at a disadvantage against those who have gone before them, extrapolate that out across other age groups.I keep hearing you can't close all the schools because the kids will fall behind.
Who are the kids going to fall behind?
If everyone had to repeat the year again it is an argument you could make, perhaps, but as it is certain kids will definitely fall behind others either in their age group or behind older ones.