This is why a lot of chronic diseases will NEVER have cures. It's more profitable to treat than to cure. Treat someone over a lifetime and milk 100k out of them. Treat someone once and present them with a 100k price tag to pay all at once and the consumer or insurance company will balk at the cost.
It's a fun conspiracy theory, but this is actually just how biology works.
There's basically four kinds of things that can go wrong with our bodies. Infections, mechanical issues, system errors, and cancer.
Infections we can cure by helping the body to kill off the infection, it's only some rare stubborn ones like AIDS that are chronic like you describe.
Mechanical issues we can fix with surgery.
System errors? That's stuff like genetic disorders where our body creates too much of hormone A or doesn't create the proper form of protein B. The problem is in our DNA and you can't cure it without rewriting our DNA (which we're getting to).
And then there's cancers, which are similar to infections, where we try to kill it (as they're doing here), though weirdly, some research suggests treating it as a chronic issue might be better for the patients.
In either case, it's not the fact that pharma is deciding "don't make a pill to cure it, just find a lifetime treatment!". It's only in the past few years that we're reaching the point where we can actually cure things that were traditionally chronic.