A probable reason is the length of time patents and especially copyright law applies, at least in the US. Although we are seeing issues with 70+ year copyright

A probable reason is the length of time patents and especially copyright law applies, at least in the US. Although we are seeing issues with 70+ year copyright with extensions after the creators death, digital technology just moves way too fast compared to classical technology. By the time a classic patent expired, other firms may have built the infrastructure to create a generic copy or even advanced the science like with light bulbs. Digital tech moves quickly and software that can be distributed across the planet in seconds and make billions in its first few years is ripe for subversion and knock offs. Maybe if digital patents applied to much more specific applications then competition could build their own version using a new code base and compete?