Why the heck does it take 8-12 weeks to process rebates?
Because it takes that long to open all the envelopes, go through all the paperwork attached, read people's handwriting, process a check request, ets.
The same reason it used to take 8-12 weeks for the IRS to process a refund check. Now it takes 2-3 weeks for the same process when you file your tax return electronically.
Interest revenue made by the promoter of the rebate in an 8 to 12 week period can be a lot of income depending upon how much the company has sold and the cost of the rebate to them.