In the real cost of running a government if any of them truly wanted to disrupt crypto and make people loose faith and money in it till is disappeared there are dozens of cheaper / faster / easier ways to do it then having James Bond sneak into an engineers lab and change chip design to implement a vulnerability that may or may not wind up in a device that people use to secure BTC / crypto.
You're assuming that the objective is to destroy confidence in the network, rather than targeted attacks.
Given that Oracle was literally founded out of a CIA project called "Project Oracle", Facebook was created out of DARPA's LifeLog, and the UK government's Investigatory Powers Act (2016) etc. demands manufacturers to insert backdoors in encryption etc., then I don't think it's particularly schizo to think that they have the ability to secretly insert certain hardware functions in a few key chip manufacturers.