It's only indirectly the IRS fault, in that they don't mandate that info on the 1099s. I pay hefty fees to the brokerages and they are supposed to provide the tax information as part of their service. They do, but they sure don't make it easy for their paying customers. One house I couldn't find it any where so I called a rep. It took the rep 35min to find the info.
All the info is in their computers and they print it up and send it to you every Jan. It would take me 5 min to program them to print 1 more # somewhere on their form and label it $ amount on which foreign taxes were paid. Everyone knows that this info is needed. sheesh