We do not "get off" on claiming that 30 days is a standard time to expect a fix. We actually think that 60 days is the timeframe for producing a fix. That is why on our upcoming advisories page we only start listing vulnerability patches as being overdue
after the 60 day mark, not 30 as you incorrectly state.
If you want to get specific about it though Microsoft is actually apart of an industry group whom wrote a specificion on vulnerability reporting and vendor handling of reported vulnerabilities. Within that standard Microsoft and other companies in the industry agree that:
"The appropriate timeframe will vary from case to case, but it is important to set a target. By convention, thirty (30) calendar days (measured from the date the Vendors acknowledges receipt of the VSR to deliver of the fix) has been established as a good
starting point for the discussions, as it often provides an appropriate balance between timeliness and thoroughness." 
So as you can see the 60 day window that eEye uses is actually *longer* than the general industry guidelines as set by Microsoft and other security companies.
Reasonable amount of time? Should take them a year to fix vulnerabilities? If you believe that then the secretly encoded brainwashing images within channel 9 productions is finally starting to pay off.
Chief Hacking Officer
eEye Digital Security
http://eEye.com/Retina - Network Security Scanner
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 - http://www.oisafety.org/