He has a valuable, entrenched product that is apparently used by a lot of people and provides value for them.
If those people won't pay a small sum to use this - or can find some easy substitute, then that could be an indication that this open-source project simply isn't that valuable.
If there is no easy substitute, and he is creating consistent value, he should be able to get some kind of revenue for something, possibly enough to pay himself and a few others to make it better.
It's not always easy, but it's not remotely irrational for him to try a few things. There's no reason for him to 'work for free' to help other people in their endeavours. They can pay him, and everyone still ends up a winner. It's called 'comparative value' - it's how most of the economy works. It's good. Apparently, he wants to 'get a job somewhere' writing code. How are his future employers going to pay him? By asking people to pay for the software that he writes. Or something along those lines.
In fact - given that he does have a 'high degree of expertise' in this open-source he made, that apparently people are using - it would make good economic sense overall if he (and possibly some others) were working on that, as opposed to him 'getting a job' elsewhere. It's a matter of plugging into the revenue stream. Again - not trivial, but something that could surely be tried.
Your post once again goes to the extremely flawed and inaccurate "If people aren't going to pay, then your thing is not good" thought, which has been proven false time and time again.
I'm going to assume that you have no background in business or commerce, which is understandable, most people on HN don't.
If people are not willing to pay for something, then it's a very strong indication that it has no economic value.
Almost by definition.
When people pay $4.00 for a Cappuccino, and are not willing to pay $1 for 'an app' - then yes - 'the app' is worth less (to them) than a cup of coffee.
Sometimes there can transactional friction, IP issues, regulatory issues which distort the market etc., but generally speaking 'price' is a very good proxy for value.
If nobody is willing to pay money for this guys product, then it is worthless, and he should probably stop wasting his time by volunteering his time to make something that nobody derives any value out of.
Those people using it would in that case obviously have something else they can use that is 'just as good', or, they just don't need it at all.
After all - if they will pay $1 for a Bic pen, and not this software, well, that doesn't bode well for how useful this software is for them.
But mostly likely, would rather seem that this software is quite valuable to many researchers. Which is good, because they would likely indeed pay for it, just as they would a pen, a book, their computer, their lab-coat, their eyeglasses, their calculator or their lunch.
If those people won't pay a small sum to use this - or can find some easy substitute, then that could be an indication that this open-source project simply isn't that valuable.
If there is no easy substitute, and he is creating consistent value, he should be able to get some kind of revenue for something, possibly enough to pay himself and a few others to make it better.
It's not always easy, but it's not remotely irrational for him to try a few things. There's no reason for him to 'work for free' to help other people in their endeavours. They can pay him, and everyone still ends up a winner. It's called 'comparative value' - it's how most of the economy works. It's good. Apparently, he wants to 'get a job somewhere' writing code. How are his future employers going to pay him? By asking people to pay for the software that he writes. Or something along those lines.
In fact - given that he does have a 'high degree of expertise' in this open-source he made, that apparently people are using - it would make good economic sense overall if he (and possibly some others) were working on that, as opposed to him 'getting a job' elsewhere. It's a matter of plugging into the revenue stream. Again - not trivial, but something that could surely be tried.