I don't see the conflict in statements.
1) Tom WANTS to play into his mid 40's.
2) Giselle has agreed to 2 more years.
2020 is possible. We posters can guess how like that is.
What is important is the commitment by all to 2 years.
Most of us have been saying that since the off-season began. It does mean SOMETHING that his contract has not been extended. As Kraft said, everyone is happy with the contact as it is. Obviously, the contract could be extended later, for 2 years, or one year at a time.
With regard to a new quarterback. A quarterback (or 2) brought in next year will have at least a full year to learn, plus 2 off-seasons.