That would be a great outcome, but this rumor is not, strictly speaking, related to DCS and Legacy. But here's hoping anyway.
I've heard this will be an expensive catalog for me...but I knew that anyways hahaha.
I am going to guess Lionel bought MTH Tooling.
Evidence:
M.T.H. 2021 Transition Plans Revealed | May 18, 2021
"The as-of-now unnamed buyers of the other O Gauge tooling will be revealed later this Summer."
Source: https://mthtrains.com/news/701
AND
^^^"this rumor is not, strictly speaking, related to DCS" - @landsteiner
liberally speaking, DCS is MTH and therefore OP is implying Lionel will announce MTH product.
AND
If you look at the squares in the background of Lionel's instagram announcement, you can make out the letters "M" "T" and "H"