FPC + Lazarus can't be compared to the Linux kernel.
I didn't compare FPC + Lazarus with the Linux kernel but, since you mention the Linux kernel, the birth of Linux was not a paid project. TTBOMK, Linus Torvald created Linux on his own free time. Posted a copy of it on usenet, other programmers found it interesting and contributed to it. Eventually, after many _unpaid_ contributions, it became clear that it was probably worth a financial investment to turn it into a capable platform that could sustain a business model.
Also, as far as Linux is concerned, if the many GNU programs had not existed, it is unclear what the ultimate fate of Linus' efforts would have been. It takes a lot of time to develop a capable compiler, linker, make, editor, etc, etc which are all required to make an O/S a usable piece of software. All that software was, at least initially, unpaid.
With big open source projects or some very important ones, it's mostly paid developers contribute to them.
That might be true but, it happens only after they get big and, before that happens, a lot of people have contributed significantly to it.
I don't want to be rude or ungraceful, but I would say FPC + Lazarus is rather a hobbyist project.
That might also be true but, the most likely reason is because the Pascal language is not very popular. If Pascal were more popular and large corporations depended on it, it might not be a "hobbyist project".
The point isn't that there aren't programmers being paid to develop open source software, the point is that, likely, the bulk of open source software is, at least initially, done by unpaid programmers. If their project manages to gather enough attention then and, more often than not, only then, are programmers eventually paid to continue developing it.
Think about GCC. Doesn't it developed mostly by corporate? Because it's a very important project.
I don't know if currently most of the development in GCC is done by paid programmers or not but, TTBOMK, Richard Stallman, who wrote GCC, wasn't paid to write it. That can be said of most, if not all, the initial suite of GNU software.
Pascal is not that important as a language. You have to accept this. This is a fact.
Not only it's a fact, it's a fairly obvious fact but, GCC was not born because someone paid for it to be developed. Both are the result of an individual's interest in the language, Richard Stallman's in the case of GCC and Florian Klämpfl in the case of FPC. In most open source projects, money goes into developing the project only after the project has attracted the attention of businesses as a potentially lucrative money-making platform.
p/s: Did you know Eclipse is from IBM and Java/Netbeans are from Sun/Oracle? They are all open source software!
Yes and the main reason Eclipse is open source is to make it more likely to succeed against what it was designed to compete against (I'll let you find out what that was.)
In the case of Java, originally it wasn't open source. It was Sun proprietary. _Presumably_, it became open source because proprietary programming languages have a tendency not to fare well in the marketplace.
Just because there are open source projects that are maintained by paid programmers does not mean that most open source projects are maintained by paid programmers. The majority of open source projects are fairly small and maintained by programmers that invest their free time in developing them.
Lastly, this discussion is _way_ off topic and, should be continued (if at all) in a thread dedicated to it. That said, I've pretty much said all I cared to say on the subject.