Some patents remain valid in USA, Brazil and a few other countries.
So that firm might try to squeeze every penny they can before the expiration of the patents.
I, for one, am happy about this. Nothing makes me happier than to see patent trolls eat themselves alive. Also, being an open source advocate, I appreciate when propriety technologies that are "good enough" can finally be used by open source applications with broad support. Unless you are pushing a ton of video, or working with high resolution (4K, 8K)/ high bit-rate videos, AVC/h.264 is perfectly fine.
For now they try to bully some smaller companies with the threat of the big legal expenses that would be needed to fight these claims.
Basically, you can consider AOM to be a licensing alliances, where the fee is zero.