This is, in fact, why Derez strategies haven’t really existed, and why that ‘tool’ of Criminal hasn’t ever been that useful.
When destroying ICE via Parasite gives better, lasting effects for more ease than De-rezzing does, that’s when the Derez strategy looks useless.
Currently, the reason to Derez instead of Destroy is that Los/Keros gives money for doing this, while Destroying doesn’t give you money. I’m unconvinced that this is a good enough reason.
It’s essentially the difference between Anarchs and Criminals. Anarchs want everything burnt down and exert more power on a small Corp board state, without caring about their own. Criminals want to get paid from whatever the Corp is doing, primarily because they need gobs of money to deal with any Corp board state because of how inefficient most of their methods are. (Aside: Shapers are also inefficient, but make money regardless of Corp board state.)
Yet, because of the fundamental power of ICE (spend once on Corp side to force spend multiple times on Runner side), Destroy is ultimately much more powerful than Derez. Especially when Derez is tied to breaking that ICE. (Currently, Rubicon and Emergency Shutdown are the most powerful Derez options because they don’t necessarily have to break the ICE that got rezzed. HOWEVER, all ICE would be unrezzed if never encountered, thus you have to have either suffered the effects of the ICE, or broken it, at least once if you can Derez it.)
I might be trying to make a Los-Rubicon deck work and have thought a whole lot about Derez strategies… >_>
EDIT: The last paragraph is one of the reasons I’m inordinately excited for Flashbang. Not because it’s good, but because it offers another option to derez without suffering/breaking the ICE. Honestly, until Criminal gets a Parasite-equivalent for Derezzing, Destroy is probably always going to be better. (Think a Program that hosts on an ICE and gains Power Counters, and when Power Counters >= Strength of ICE, can pay 2cr to Derez that ICE.)