Three points.
- These Diesel-electrics are Western - quieter than their Soviet-made or Chinese contemporaries.
- Torpedoes themselves are loud; firing torpedoes provides, giving time for a carrier to react.
Yes, carriers are large, and are unlikely to evade all of a spread of torpedoes. But, not knowing the nature of the evasion before hand, a spread of torpedoes would be necessary to hit. Wire guided torpedoes provide a better chance of a hit, but most subs can only guide one or two at a time.
Which brings us to my next point.
- Aircraft carriers are REALLY big. A hit from a modern torpedo or two, is probably not going to kill one.
Ruin it's ability to continue operations? Probably.
Cause it to leave the area of operations? Probably.
But probably not sink it.
A nuke warhead is a different proposition, but if you are opening WW III with nuke strikes on carriers... having a tactical navy won't matter much. This will become strategical level nukes strikes before the 11 o'clock news.
Until then, aircraft carriers are useful for projecting (national) strength by
providing an airbase that can be moved as needed (however expensive to operate).
Uncle Ted