"David A. Scott" writes:

In many ways the Hubble is a failure they never even cut the
mirror correctly. [...] Hubble could have done much
more if it was ground correctly. The extra lenses added to it
failed to make it as good as it should have been.

This is not true, except for the very first batch of instruments, all
long since replaced. There are no additional lenses in any of the
insruments designed since the flaw was uncovered.
In all the new instrucments, since they need one or more
mirrors to direct the light within their own optics, they just need to
make one or more of these mirrors not quite flat. This restores diffraction
limited optical performance without adding any new elements.

Lou Scheffer