If they confirmed that, then I'd sell it or move it to another room and replace it. Not the inexpensive answer, but probably the answer unfortunately. I presumed "most discs" meant even older ones, which would indicate something going south in the player usually, but only new discs would mean it is a decoder issue. I've run into it with Oppo before and since they are local, I took them one disc so they could see it and they said the studios release new encoding on their movies every few months so it will continue to happen going forward. Since the most recent one though, I haven't run into any discs that I can't play.
This really is outrageous if you think about it. Recycling is a very benign word for what actually happens. The truth is that very little from an electronics device is salvageable. Recycling is really a euphemism for dump our toxic junk on the third world.
I suspect LG's actions may be illegal, as by federal law a manufacturer is obliged to supply parts for seven years from the date of last manufacture. I don't know if firmware can be put in the category of spare parts. There is also a reasonable effort get out issue. So if a supplier runs out of a particular IC, as they are generally only manufactured once, that gets them off the hook.
The other issue is that the studios are in charge of the code changes, and there could well be issues in the BIOS of the players, that make it impossible for the manufacturers to comply with issues they could not foresee.
I have long thought this issue requires changes to federal regulations. Unfortunately the politicians are star struck by Hollywood creeps, especially the current outfit.
One solution for you is to consider building an HTPC, with Arcsoft software. I think arc soft plan to continue to stay in the game. They do require periodic fees to cover the cost of writing the software for updates, which is reasonable.
The other thing, rather than going the recycling route, manufacturers should consider charging for these firmware updates required by the absolute sewers inhabiting Hollywood. The OP should note that they are the real villains and not LG. So rather than boycott LG, you should consider boycotting Hollywood's offerings.