CKK,
None of the Rabbonim & R”Y’s mentioned that in their letter. It is obvious that the Rabbonim & R”Y’s WANT our bachorim to learn Torah in E”Y the longer the better. The Rabbonim & R”Y’s had the opportunity to say otherwise in the letter, especially considering NASI’s personal have been pushing that option long before the letter, and yet the Rabbonim & R”Y’s specifically did NOT give that as a reason in the letter — specifically because they do not want that to happen. They value the learning as a priority.