We are not talking about HP here, this is general.
I am glad you are one of the people who have a shitload of money to start a case like that, and to support continual financing of the legal proceedings in a foreign country with different laws, local and foreign lawyers and law firms and IP specialists.
Like I've already pointed out very clearly normally this is not the case with most developers, like small companies or freelancers.
The contract in this case worth less than the paper it is written on.
Obviously if someone is this bloody rich, can work on a project for years, have zero income and still being able to start suing the other company under those circumstances: god bless him, he is doing it to teach those bastards a lesson, and not because he does need any of the money for real - it is very clear from the situation described.
Unfortunately many people are not in the same situation and do need an income for living a life, quite possibly much lower quality than what they could afford if they were not so determined to make a good product and sacrifice years of their life on such a bizarre idea.
The idea of loosing even more money is not that attractive to developers on a very tight budget, possibly looking for real jobs after incidents like this. Actually in the fields mentioned: the real IT world. Not niche machines, not games nothing really creative just get a monthly income and hope to forget all the shit happened before.