Still getting emails from blocked sender

I keep getting spam emails from the same senders even though I've already blocked their domains, as well as all of the other email addresses/domains that were found in the message sources. 

• WHY am I still receiving messages from domains that are blocked??
• Why is there no option to simply block a sender's I.P. address?

All of the spam I receive comes from the same 3 or 4 I.P. addresses, but they have tons of domains at their disposal to spam people with.

I don't want to resort to creating a new 'rule' every time these idiots come up with a new domain to send their spam from. So before you suggest that I create a new rule for each and every one of these email addresses, my response to that is NO. I shouldn't have to. Aside from the fact that doing such a thing would be far too time-consuming, when I block someone, I expect my email provider to perform that function properly and without fail.