It'd be easy enough to build hardware that would stop working, but to keep working but to make many pieces of software fail in specified ways seems like a very difficult task.
Coming from someone with degrees in both Electrical Engineering & Computer Science, I totally agree with you. The "infected computer chip" story sounds like a load of crap some creative writer came up with based on pop-science TV shows.
The real-world financial burden that Reagan applied to the Soviets by escalating the arms race is more than enough justification for their accelerated collapse. The author didn't need to come up with goofy, albeit entertaining, science fiction to further explain what happened.
I'd heard the stolen software version of the story before, and I'd wondered about that - that the hardware interface of a Soviet pipeline would be similar enough to a Canadian pipeline for custom software written for one would work on the other without significant rework strikes me as unlikely.