So the relatively new Korean Samsung does not support it, but (coincidently) new Chinese TCL being delivered today does.

Not as bleak as post indicates:

Here are the key details:
Recent Rule Change: On October 28, 2025, the FCC adopted new rules to accelerate the transition to NextGen TV (ATSC 3.0) by ending the previous requirement for stations to maintain an ATSC 1.0 simulcast indefinitely.

Voluntary Transition: The transition remains market-driven and voluntary. The new rules give broadcasters more flexibility and authority to set their own conversion schedules.
Conditions Apply: Stations must file a specific application with the FCC's Media Bureau to cease ATSC 1.0 transmission and must demonstrate how they will maintain service coverage and access for viewers who do not have 3.0-compatible devices.

No Mandatory Cutoff Date: There is no single, mandatory nationwide cutoff date imposed by the FCC. Instead, the process will happen on a market-by-market basis.
Current Simulcast Requirement: Until a station's application to stop is approved, current rules still require stations to simulcast their primary programming stream in ATSC 1.0, typically through a "host" station partnership, to ensure existing viewers are not immediately cut off. This requirement was extended to at least mid-2027 in a previous decision.

Consumer Impact: The change means that viewers relying solely on over-the-air broadcasts with older TVs or antennas may eventually need to acquire an external ATSC 3.0 tuner/adapter or a new TV with a built-in 3.0 tuner to continue receiving those channels.

Jeff