They patented the original Transformer encoder-decoder architecture. But most modern models are built either only out of encoders (the BERT family) or only out of decoders (the GPT family).
Even if they wanted to enforce their patent, they couldn't. It's a classic problem with patenting things that every lawyer warns you about "what if someone could make a change to circumvent your patent".
Are you kidding? There are 30 claims, it's an hours' work to make complete sense of how these work together and what they possibly do/do not cover. I've filed my own patents so have read thru enough of prior art and am not doing it for a pointless internet argument.
IANAL. I looked through the patent, not just the Claims. I certainly didn't read all of it. But while it leaves open many possible variations, it's a patent for sequence transduction and it's quite explicit everywhere that the system comprises a decoder and an encoder (see Claim 1, the most vague) and nowhere did I see any hint that you could leave out one or the other or that you could leave out the encoder-decoder attention submodule (the "degenerate use-case" you suggested). The patent is only about sequence transduction (e.g. in translation).
Now an encoder+decoder is very similar to a decoder-only transformer, but it's certainly an inventive step to make that modification and I'm pretty sure the patent doesn't contain it. It does describe all the other pieces of a decoder/encoder-only transformer though, despite not being covered by any of the claims, and I have no idea what a court would think about that since IANAL.
Google's Transformer patent isn't relevant to GPT at all. https://patents.google.com/patent/US10452978B2/en
They patented the original Transformer encoder-decoder architecture. But most modern models are built either only out of encoders (the BERT family) or only out of decoders (the GPT family).
Even if they wanted to enforce their patent, they couldn't. It's a classic problem with patenting things that every lawyer warns you about "what if someone could make a change to circumvent your patent".