I am not an engineer
, and have no own experience with SS groundtackle.
I guess for most boats the gear
lives on the bow/anchor locker, not in seawater.
When in seawater, yes a SS anchor is more noble than the zinc on the chain, so slowly the zinc will be sacrificed, and a rusty appearance will develop. This might take one or two years? One could then cut a meter from the chain, each year or second year.
To have a galvanised chain with a SS anchor, again the zinc on the anchor will slowly disappear, when immersed in seawater.
I must say, I have seen both scenarios, that is combining both SS and galvanised steel in the same groundtackle, where the zinc on chain or zinc on anchor still looks good after a few years. Maybe having the anchor dug into mud or sand is reducing the galvanic corrosion.
On edit: When I purchased my boat
it had 2 galv. anchors on the bow and both was on galv chain, but both had a SS swivel between anchor and chain. Previous owners anchored very often,but... I could not see any loss of zinc on anchor or chain. BTW, I removed both swivels, for different reasons.
Re strength: if the zinc disappears from a few links..... will not have an affect strength at all. For the chain or anchor to lose its strength, then all
the zinc need to have gone and the steel starting to be sacrificed. Unlikely scenario as the boatowner would have taken action by then.... I hope.
Of course, then there is the issue if SS should be used in groundtackle at all. But that is another can of worms.
When I purchased my boat it had 2 galv anchors on the bow, both on galv chain. Both had a SS swivel between anchor and chain. One anchor was used extensively over a period of 10 years or so (although was about twice that age I guess), that piece of chain and anchor were rusty. The other anchor and chain were 2 years old and had been the primary anchor since then, and in near perfect condition. BTW I removed both swivels, for different reasons.