A good knife is subjective and most of the top brands make knives for many different needs and or opinions.

For me its the right combination of edge retention and ease of sharpening.

Generally the longer a knife holds an edge the harder it is to sharpen and really to be honest IMO the super steels don't hold the edge enough longer to justify how hard they are to sharpen. Personally I like Aus-8 , 1095 , Sandvik and then some exceptions like 420hc which is good if done right (like by buck)

The harder steels are harder to sharpen and can be brittle.

I see a lot of people say some knives go a long time without needing sharpened but they must have different ideas than myself. They all require a fair amount of work in my experience to work they way I want them to.

A real sharp knife has a real fine edge and a real fine edge requires maintenance.