I pay Netflix a nominal fee each month and whenever I feel like it I can choose to watch between hundreds of shows (currently working through Penny Dreadful), without having to hunt down a torrent for it. Especially a torrent of good enough quality.
Same with Steam. Sure, I could try to find a game to download via torrent, but I know I can find it on Steam, often at a steep discount (or put it on my wishlist and wait until the inevitable one arrives and they notify me of it).
Additionally, I know it won't have any malware or viruses hidden in it, and will be the most up to date version (seriously, try finding torrents that are up to date for most things, it's almost impossible).
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.
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.
And honestly, this idea of perfect meritocracy, the idea that if you don't get funded, then your project was crap, has been disproven a long time ago. There was a kickstarter that raised insane amounts of money for someone to make potato salad. Not as a product, but making a bowl of potato salad for themselves.