What is the most egregious about software patents is that they work only because in the first few decades of software development no patents could be obtained f

What is the most egregious about software patents is that they work only because in the first few decades of software development no patents could be obtained for software. Anyone who patents now some kind of software algorithm is able to write any practical implementation of the patented algorithm only by incorporating many techniques that have been invented earlier, but they have never been patented, even if typically they would have had much better reasons to be granted a patent than the newly patented algorithm. If it would have been possible to patent software since the beginning, the software industry could never have existed, due to mutual destruction that would have blocked any development.