They didn't before.
You should contact Gigabyte regarding this. This was a major issue awhile back and many board manufacturers were repairing boards free of charge. It may be too late now but it's worth a try.
Other than than that, you have several options. You can take it to a shop and see if they'll repair it. I would go ahead and have them all replaced because others will follow.
Another option is to get the capacitors yourself and attempt to solder them yourself. You can get replacement capacitors from
Digikey. Should cost about $15.00 and you better have good soldering skills. I would invest in a de-soldering kit from Radio Shack as well.
Other than that, just buy a new board as it's also possible that the two that went took something else with it on the board, possibly even the CPU.