Because immunity varies by disease.
Chicken pox? Pretty much one and done. COVID? Falls off rapidly after 3 months, whether you catch it or get the vaccine
Plus, every mutation is a dice roll on how much existing immunity will apply. It could be exactly the same as the last strain, or the old immunity might not help at all
Yeah, except they federate. They keep lists about who they federate, defederate, and know of in machine readable format
IDK if you can convince it to run on Linux, but I’ve been pretty happy with paint.net lately
It’s basically a newer project like gimp. It’s got the core abilities and appearance of Photoshop. Feature wise, it’s less than gimp or Photoshop, but what it has works decently well
Most importantly for me, the UX is much better than gimp… Not as good as Photoshop, but I find stuff is usually where I’d expect it to be
Obviously it’s built on .net, so theoretically it could run native on Linux… Not sure if anyone has done the work to make that actually happen
Not a feat of engineering, a feat of marketing