That would be a problem with the host - not with Korg. If you have to change your computer for a non Korg reason, then how can it be anything to do with Korg?So what If I decided to buy a new mac because only that one will run the new version of my host that fixes a longstanding bug that prevents me from working???
If you changed your equipment, that's up to you - no-one made you do it.
If you want your fully working non dongled KLC back - get your old Mac back - simple as that.
By the way, having a dongle is one of the few things that helps software retain it's value, as it can't simply be installed, copied & then sold on.
EVERYTHING loses money. I paid nearly £2000 from my roland XP80 & it's expansion boards & it's worth about £400 now. Same losses in value can be attributed to my past gear like my Akai S5000, my Fostem DMT8 etc etc. By those standards your korg KLC has retained it's value quite well.
Also hardware versions of all the synths in the collection are available. If you have such a problem with a dongle or wiating for an update - there's your answer.
It'll cost a lot more than your KLC did, wont be anywhere near as flexible, , you'll need extra midi cables & audio leads, but I'm guessing you knew this already & that's why you bought KLC to begin with.
Whatever your opinions on my analogy, one thing is irrefutable - if you still had your PPC Mac - we wouldn't be having this conversation.
Respectfully
Geoff