I agree with much of what you stated in your post... except for the above...
They want a brand name to add credence to their core business, TV's.
For TCL AVR's and 2-channel stereo has never and will never be their core business. In the way that Blu-ray players and headphones are not Oppo's core business. They will take what they need and if it works for them, the brands will live on, if not they will sell it to the highest bidder.

The interest in the longterm is where does TCL take Onkyo/Pioneer products... but the immediate change will sit with changes of distribution and warranty handling.

so why exactly would they shut it down immediately after they bought it?

Receivers are joining cassette decks, CD players, VCRs and DVD players.

IF you're going to make a receiver, you'd better be a very big company with lots of resources for design to keep up with all the HDMI and Surround Format changes (same thing that killed the specialist DVD player), or the models better be critical to your companies survival.

Whose left:
Main Stream: Denon/Marantz, Sony, Yamaha.... Pioneer/Onkyo/Integra
Specialty: Anthem, Arcam, NAD, Rotel

Too many for the small percentage of sales in a category that continues to erode. Currently a large portion of which are loyalists upgrading their home theaters for 4K switching, with nothing mainstream on the horizon that will have them replace it again.

Our Industry has made AV so difficult, that by the time they settle on a TV purchase, they don't want to deal with any more decisions, "soundbar's good enough for what we watch".

I guess it depends on how much they paid and how much they could get if they sell everything. They probably own real estate, existing inventory and other assets but they have been waging an uphill battle to gain the dealers lost.

Has anyone seen the details of the sale, yet?

So does this deal include Integra?

“The agreement does not cover such home-audio components as A/V receivers, says an executive with Onkyo USA, a privately held sales and marketing organization that markets Onkyo, Pioneer, Integra and Esoteric audio products.”

OK, i feel a little bit better. :)

I love the discussions this leads too, almost "who's on first".

Customer: I have a Pioneer car stereo and my friend had a Pioneer Elite DVD player he really liked. I'd like to use that for my system.

Integrator: No problem, however those are no longer the same company.

Customer: but they have the exact same logo...

Integrator: I know, it's confusing, but they aren't the same company. Pioneer Home is now owned by Onkyo..

Customer: Oh onkyo! I have one of their sound bars! Lets use them for the receiver then!

Integrator: Can do, but again, not the same company.

Customer, but they also use the same logo...

Integrator: I know, but not the same company...

Customer: Then who would you recommend?

Integrator: How about Integra? They have many great integration features for your control system and I have used them for quite a while..

Customer: OK, but I've never heard of them. Who owns them?

Integrator: Onkyo..

Customer: which Onkyo? Never mind F**K this I'll just go with a Denon. Anything as long as its not Marantz, I had a bad experience once.

Integrator: Uh..... got some bad news for you...

Sarcasm button turned off... Seriously though there is so much brand merging/exclusivity/licensing/muddying, it's a joke. I know we all sell ourselves and the experience we can provide, but with only a little research by the customer and it becomes a treatise on mergers and acquisitions....

Someone with some money (and who has been in hibernation for a while) must be wondering if H.H.Scott or Fisher have any brand equity. Grandpa and maybe Dad (and a few old timers that hang out here) loved these brands.

The Onkyo brand being kicked around is just a continuation of the Scott and Fisher story.

Integrator: Tell you what, let’s go with Yamaha. They make really nice motorcycles. Now, let’s talk speakers

Fisher was diluted to just a shade yellower than clear water about a decade ago.

Sanyo had bought it in the late-'70s or early-'80s, so it was pretty diluted before.

If there's one thing that could have prevented market confusion, it's consistency in brands, over time. However, when market forces, bad management or a string of failures cause companies to falter or fail, someone is always there to snap them up and either whore them out or dismantle it, to get rid of what isn't wanted/needed by the buyer. Then, potential clients ask about brands that aren't well-known and are disappointed when we haven't heard of them, or decide that we aren't who they want because we haven't heard of every brand.

"I used to like Thrusters- can we get some of those?".

You can take crap, like Goldstar and rebrand it. LG has done very well, even though they have lots of crap.