In all the time I was in the Witnesses, I too was taught that the "creative days" of Genesis were 7000 years long. What is the scriptural evidence supporting that?
In the Bible, it also says that to God a 1000 years is a day. Therefore if taking everything in the bible literally, then God changed to a new model of clock after creation.
That the earth and all living things were created in only 42,000 years goes against everything known by modern science. It seems as though the Witnesses pick and choose what passages in the Bible to take literally and what to take figuratively. The "7000-year-day" theory only works to support their "end-is-near" predictions, specifically the 1975 [we didn't say THAT!] prophecy.
"You can't have everything, where would you put it?" -- Steven Wright