I think that's silly. There could have been hundreds of well-paid FOSS jobs in 2013. That doesn't matter at all if there are none in 2017. It doesn't even prove anyone was ever hired for that job, only that it was posted.
There's certainly analytical value in having every FOSS job you could have ever seen, but none for the end user.
There's certainly analytical value in having every FOSS job you could have ever seen, but none for the end user.