Some of you guys need to step back, take a breath, and then look at it from a systems approach. K-Line, Weaver, any other OEM manufacture that used TAS is obsolete and unsupported, period. Those that used QSI tech are pretty much in the same boat.
Now for some of those system, Lionel still has R2LC and RS Power Supplies, RS 4.0 and 5.0 sound boards that you can use to fix those engine. OF course TAS bottom board was a combination mother board, Motor Driver, and cruise control with Tach. Not Lionel's model, So if motor drive goes your out of luck.
You can always go and get a basic reverse unit and sound card. But draw back will be loss of command, and loss of cruise control.
ERR filled that gap, and besides making an upgrade also made a repair package for those OEM TAS units. Or K-Line and Lionel ODY units. Unfortunately gone.
MTH us still a viable upgrade to those K-Line, Brass and Cast Weaver, Atlas etc.... You can run it conventional, DCS, or DCC if you want to move away from Legacy and DCS.
I am not sure how many folks are just TMCC only? I would think a small group. Or Legacy or DCS only. Choices to make, but this is no different then something going obsolete after a long run.
PS-2 3V is a great board, but the microprocessor is gone. Same with PS-1 chips. The PIC chip is obsolete. What remaining stock exist is in MTH hands, but they can only make so many more sounds chips before they are gone.
But let's not forget the used market. I can keep PS-1 engines running for another decade or more. Add Marty, John, and others, let alone I fix most boards. It is rare that I have to replace, though it does happen.
So, think how many R2LC, RS Power Supplies, RS 4.0/5.0 boards, and mother boards are out on the market from upgrades.
But it is true that ONLY MTH has used a model to make their latest Tech backward compatible. I can fix a PS-1 or PS-2 5V with a PS-2 3V and Now PS-3. I am sure when PS-4 comes out it will be the repair part for PS-3 engines. New runs of MTH engine become the source of new motors and such to repair the first run. It has been this simplicity in approach that has allowed MTH engine to be kept running. Not cosmetic parts, but the main items to keep an engine running. This means there has not been much in the area of new features and such, but the approach to not make every engine a snowflake (one of a kind design) pays off. They cater to the middle of the road approach to this.
If your a Lionel only type of guy, then you have picked your poison and need to live with it. Sure complain to management, but you bought in to their approach. Buy some LC+ and go run trains. TMCC is obsolete. By the way, that makes my layout obsolete. It is K-Line track with TMCC and mostly TMCC engine, along with some Conventional and PS-1 engines. But I seriously imagine I will be dead and buried and my grandkids can still run my layout for a while.
This is not the end of the world, but it is sad. Jon Z took the best of the TMCC stuff, went Back EMF, and packaged a wonderful product to make engines TMCC engine. OF course the industry is well beyond TMCC and 3 basic function controls. Integrated smoke, ditch lights, flashing MARS, markers, Rule 17 are all highly desired by much of the market, and TMCC could not give you this. Once you add GRJ Super Chuffer, Tach control and aux lighting package, your well over $300 in just parts and you still fell short of PS or Legacy features. As Marty would say, "it is what it is". G