Sisvel allows you to pay them if you believe their claims, they haven't actually taken anyone not paying to court yet to prove that. The only court cases for VP9/AV1 from Sisvel so far have been their patents being found invalid/irrelevant.

Dolby is somewhat more interesting in that rather than scare tactics, media hype, and attempting to form a pool about it they are actually taking a patent assertion claim to court.

That crowd are just deeply concerned one of their lucrative revenue streams is disappearing.

So they seem to be attempting to pull a fast one and use unproven claims to try and convert their competitor into a replacement revenue source.

It'll probably be a case of whoever has the best lawyers + contacts + persistence wins.

But it'll be interesting if discovery shows evidence they know they don't have a case and are trying it anyway. "Piercing the corporate veil" can theoretically be a consequence of that AFAIK.

How does how they bill for their product, matter in terms of if their lawsuit holds merit?

That doesn’t prove their claims are valid.

I can claim the same and offer licenses per device.

Can you point to any other patent lawsuit over AV1? AFAIK the Dolby case is the first.