To a certain extent, your are describing the status quo. If the spam filters catch the offending content, it is either rejected or reported for moderator review. Am not sure why sometimes the content is viewable, but once a moderator spam cleans, the account and content are removed. I usually review the system reports first as the automated clean will close member reports caused by the same spammer.
So far, if a spammer slips by, worst case it just takes more effort to clean up. Given my background in IS, I tend to want to prevent as many bad actors from getting a beachhead, but then Amir reminds me to lighten up as ASR is not exactly mission critical. There is only so much we need to do.