Sure, everyone can learn, but what leads to mediocrity is a lack of desire to learn.
You can certainly structure your organisation around that and achieve great results. There’s no need for excellent tech to solve most problems. That’s ostensibly true for almost everything, because our society wouldn’t be able to survive if everything needed to be excellent.
A lot of different things can lead to mediocrity, and lack of desire to learn is only one of them.
Sometimes you want to learn, but your talents fail you.
Sometimes you want to learn, and you learn from someone who isn't good at the thing.
Sometimes you want to learn, and your environment punishes effectiveness.
Sometimes you want to learn, and you learn correctly for the wrong context.
Yes, people who give a damn about doing their job well are often good employees. But the converse is not true: many people who are not good employees do in fact care a great deal. There's no need to convert a descriptive statement about results into a moral judgement of a person's work ethic, and it's often just not factually correct to do so.
> Sometimes you want to learn, but your talents fail you.
> Sometimes you want to learn, and you learn from someone who isn't good at the thing.
> Sometimes you want to learn, and your environment punishes effectiveness.
> Sometimes you want to learn, and you learn correctly for the wrong context.
Should you just blame not having learned on the that and call it a day?
Sure, some people learn without much effort, but I’ve seen an equal amount of people that had to put it a massive amount of effort to be considered ‘smart’ (whatever that means).
I think I consider “well, I tried, it didn’t work, so it’s forever impossible” to be the definition of mediocre. That’s actually still pretty good, as many don’t even try, they’ll give something up as impossible before even starting.
I know people have reasons for that, but I don’t like it.
Your framing is someone making the immediate assumption that any failure derives from barriers beyond their control. And I agree, that's just as incorrect as assuming that any failure is due to barriers beyond their control. (It's also really demotivating.) But I think your framing is overly judgmental, because in fact most people who struggle at something have tried many times not to, they just haven't succeeded.
When speaking of other people, you often do not have good context on what they have or haven't tried. They have enormous context that you don't, often context that would be difficult or possible for you to understand from the outside even if you did have it. And to confidently judge that they just don't care without that context, without any awareness of what they have or haven't done, assumes way too much.
For me, doing advanced mathematics is easier than not feeling self-conscious when I talk to a grocery store clerk. Founding a company is easier than reliably keeping the clutter off of my desk. Walking many miles is easier than doing a push-up. I could explain to you why these things make sense within my particular context, but it would take many, many pages of trying to tell you who I am to do that. If you were to judge that I don't care about not being socially awkward, or that I don't care about having a clean room, you would be wrong - those things are just harder for me than they are for for the average person, and I choose (implicitly or explicitly) to put my efforts elsewhere.
I don't think that recognizing that is accepting mediocrity. I believe in excellence a great deal! But I think that if you want to seek excellence, you have to do it in ways that recognize what you are. Most of the time, you have to work with what you are and figure out ways to make that work. Once in a great while, something about what you are is so fundamentally at odds with what you want that you have to, at tremendous effort, change yourself. But the latter isn't something you can do every day or in every way.
"I've tried, so it's forever impossible" isn't the position I'm arguing for. The position I'm arguing for is: "I've tried, and it was very difficult, maybe more difficult for me than it is for you. I'm a human being whose resources and motivation (and judgment!) are finite, so I had to make a choice between working on this very hard thing and working on something else or taking some time to recuperate, and this time I decided some other option was better."
You can certainly structure your organisation around that and achieve great results. There’s no need for excellent tech to solve most problems. That’s ostensibly true for almost everything, because our society wouldn’t be able to survive if everything needed to be excellent.