Engineer-types certainly do try to loophole their way around the law in a way that's not how the law actually works, but this article is not really engaging in that I don't think (for one, it calls out the practice).
Cablevision is absolutely by its terms hugely reliant on the nitty-gritty technical details of how the DVR service there worked. The court had to kind of wind itself up in knots to work around the existing MAI v. Peak precedent (copies to RAM are actionable infringing copies) and the fact that the service existed just to make these copies, so it gets very in the weeds on how things are stored and the amount of time things are in buffers and so on.
Ultimately, it's probably true the most important thing was that Cablevision were an established player in an existing, uncontroversial market and they were making an iteration on the already allowed and understood "time-shifting" recording systems. But other players in the market shouldn't really be faulted for taking the court at its word that the details actually mattered. Sometimes they really do!
MAI v. Peak, mentioned in the article and above in my comment is a great example of that: the 9th Circuit holds that a computer copying the OS into RAM is a "copy" for the Copyright Act, thanks to the statutory definition of a work being "fixed." Result: a repair technician violates copyright by turning on the computer because he doesn't have a license. This is kind of the polar opposite type of decision to, say, Aereo's case: it's actually quite disruptive but hinges more on the literal definitions in the law and things like the computer not being on already, thus requiring the "copy" to be made. Congress actually changed the Copyright Act to counter this decision but in an extremely specific way, so the general "stuff in RAM is fixed and therefore a copy" principle remains and comes up often.
Aereo lost because they would upset the applecart of retransmission fees, Locast similarly though for nominally quite different reasons. It can be quite difficult to tell in advance if you're going to get a "letter of the law" decision from the courts or something more results-oriented, even from the same court.
An often-unappreciated wrinkle is the more or less total dysfunction of Congress leading to court decisions taking on ever more importance. The courts themselves aren't blind to this, leading probably to more results-oriented decisionmaking than there might be otherwise.