ASW is no different to any form of defence...it's all just insurance.
As to third world ASW capabilities...are you aware the argies had a free pot at some of our war canoes during the Falklands from their one and only serviceable SSK. the only reason they did not scupper the whole littoral operation was because their top weapons man had accidently wired up the torps arse about face.
It's all documented in the
Proceeding, The USN magazine
circa 45 countries have a submarine force and virtually every developed maritime nation still has an MPA force with an ASW capability.
Whatever, for a land-locked nation that has no navy, and nothing like aircraft carriers to protect, I guess you are right, we don't need this expensive ASW sh1T.
Oh...wait mo, what's all this wet stuff all around and what are they building in those huge **** off sheds at Rosyth