For the millet "pdf dll for .net buy" a huge commercial libraries. What is Your best this huge list? Now a high competition in IT, a huge number of programming languages that follow each other.
In due time searched for the counterparts, but libraries not found standing. Is usually write individually to each firm.
That's it. There is a project, wrote it. Got his money. Some parts of it decided to monetize, that would still make money.
But why write if it is ready flexible enough - that is my system?
I'm talking about Your system not heard. And why should I buy Your system if I have a staff of highly skilled programmers who write expensive software. What You were looking for because You were too lazy/didn't know/did not understand/did not want to understand, others take write. If You think of something which is not on the market, then Yes.
What customer focus - software companies, nasoftware, or maybe you can earn as freelancers (they should be very cheap, but they are not for long I think)?
Sowftware companies have a huge staff of programmers, they can write. Freelancer is the point? He charges by the hour, it is more profitable to write, and if the freelancer with the experience, he's already a huge number of ready code which goes from project to project, it Your library is not particularly useful if there is something unique.
So what income can be expected in the near future - months, the first couple of years?
No, you don't have anything written and not sold. You have not even decided what you will write and to whom to sell.
How to spin? (Habr - of course, but somehow it is weak)
You have a budget for promotion will be higher Your earnings. On habré not one You take off.
I foresee answers "you life behind, now opensores rules".
You are not right.
But I don't see him profit.
It is only Your vision.
And serious project, which runs over several people, as you do not want to give away for free, hoping only for some donuts.
And then there are the paid tech support. As an example look at how much the paid support nginx, there is an amount of $2500. And to write it started only a few people. You are confusing the idea of open Source is NOT free software is software with open source.
There are five of us, and no one - never.
It's You main support opensource is due to the investment of large companies, which this software uses. For example the Creator of the WhatsApp zadonatil $1 000 000
And the most important thing. If you want to sell something, You the skill of programming the least need.