I am sure Lionel took the trouble to develop software to interface S gauge Legacy with DCC because DCC is the dominant command control system in S. They were missing at least a third of a relatively small market. Unfortunately they did not also include a scale wheel option since most of the DCC users have layouts with scale rail. In S gauge there is essentially no DCS in use. Up until the MTH deliveries this month there was only one DCS engine ever made in S gauge.
If operators want Lionel to develop the DCC interface software for the O gauge Legacy boards they need to communicate that to Lionel. All I ever hear about in O gauge is Bluetooth and compatibility between Legacy and LionChief 2.0 or + or whatever controllers. I personally use only Legacy on my S gauge layout, many engines are conventional or FlyerChief that were converted to TMCC.
This is why I keep preaching that we need a converter board that takes basic TMCC signal commands and converts them to DCC commands. You can continue to use your remotes but also control a DCC locomotive.