Depending on who and what the system is ... there may / may not be a backup.
For example ... recently someone I know had applied for a job ... however the job disappeared from monster and they were unsure of the exact spec and had been called for an interview. A quick google on the job position and I found it ... got to the page saying it had been removed ... so I checked googles cache and there it was.
So its been "removed" by monster .. but it was still there in googles cache ... then as has been said there are systems like archive.org that even still have my old company website page
which is quite cool every time I get nostalgic
though I dissolved the company in 2003 I think.
So ... in a way the answer is yes / no
Really it depends on the specifics.