I actually generally agree with your assessment here. Modern things that are generally labeled as 'philosophy' and only 'philosophy' are rather abstract and with very little clarity as to their usefulness. Most of the useful philosophical ideas were indeed established back before science was fully autonomous, but even as recently as the works of sir Karl Popper (1902-1994; the father of the idea that scientific theories must be 'falsifiable') have had a very noticeable influence in the sciences. What's important to note however, is that Popper's writings were much more practical and grounded down to the act and methods of science, than any of the writings of Plato ever were for example. And that's really the point I'm getting at; philosophy has shifted more from being a useful 'subject', to being a useful approach. The art of philosophical argumentation and elaboration of ideas is still very much relevant and useful as it ever was, it's just going to be finding it's niches in more and more applied areas, to the point where people will forget they're even discussing philosophy.

Any major breakthroughs in philosophy are almost certainly going to come from philosophically-minded specialists (e.g. scientists/engineers/politicians/linguists/mathematicians/etc) in the future. But just because it doesn't carry the big overarching label of "philosophy" doesn't mean that it is not. I mean, the definition of philosophy itself is so vague, that you could say that it is simply the byproduct of any exploration that uses philosophical tools (e.g. formal logic/logical fallacies), so it really doesn't go against what you're saying at all.

I agree that if all one's doing now is studying philosophy, and philosophy only, it's gonna be hard to contribute anything terribly useful to society (unless you can get a job as a historian). But the tools that philosophy gives us should never be discarded because they are ultimately the atomic building blocks that let us know whether we're on the right track or not, and thus, thinking philosophically is of critical importance. And that is where philosophy is now. It is not a field of it's own, it is scattered throughout several other fields, but the art is still very much in tact. It this bad misconception that gives philosophy these lazy/useless/idealist connotations. And that is unfortunate, because there is much people can learn from thinking philosophically, that they do not (unfortunately) seem to gain just from thinking 'scientifically'. I'm going to blame this on training/education rather than the designation of the field itself, since science should teach how to think critically, but the practice of this does not seem to extend beyond the student's specific/applied area from my experience. Philosophy helps here because the whole point of it is to train a person's entire outlook to process information critically, rather than only apply that approach to certain specific/narrow areas.

tl;dr: Philosophy is the mathematical language of reason, and good reasoning skills should be important for everybody. However, applied philosophy within specific domains (e.g. ethics/math/politics/etc) is likely to be the only way we will continue to make more philosophical advancements in the future. Arguing that we don't need philosophy anymore because now we have science, is like arguing that we don't need math anymore because now we have programming; both are important in their own specialized ways because of the approaches they allow.