I have no opinion on patents one way or the other, and you have some interesting points about the evolving statues and case law surrounding patents. No arguments there.
But I don't think the things you mentioned are really relevant because patents are just not a viable strategy for _seed_ level startups, and that was just as true 2012-2016 (the seed boom) as it is today. Litigation may be getting more expensive, but it is a moot point because it was already prohibitively expensive for seed startups when it was "cheap." For a company that has only raised in the 500k to 1.5m range with negligible revenue (as would be usual for a seed startup), litigation is off the table.
I also find your reference to the BlackBerry case to be totally out of left field. Under no possible definition of the word "seed startup" could NTP possibly ever be considered one. So how is the example relevant?
Do you have any examples of actual startups that use patents as part of the strategy? There are different definitions of startups, but no one considers a non-practicing patent holding company founded in 1992 to be a startup.
I feel like you have an axe to grind about patents, which is fine, but I honestly don't think there is any relation to the decrease in seed startup funding.