alt Hacker News(assume when you say "permanent DST" you mean "permanent Summer Time" since "DST" is just a description of the overall switching convention, not any particular season)
Interestingly, in Ireland, the time definitions are reversed from most places - summer is standard, "Winter Time" is the deviation. This has the effect of aligning the "official" time with mainland Europe (Irish Standard Time = Central European Time) in theory, but never in practice.
Given that, if Ireland were to adopt the EU's plans to drop DST, there's a reasonable chance they could keep summer time.
In the US we switch between "(zone) standard time" to "(zone) daylight time" - Eastern Standard Time to Eastern Daylight Time.
So "permanent daylight saving time" makes sense to us since we use the term "daylight time" where Europeans tend to call it "summer time."
Still true that DST really just describes the overall time-changing process, just giving some insight into why the phrase makes sense to us.