Why is digital copyright seemingly impotent compared to its physical counterpart?

I often hear on the news about patent infringements being enforced on physical products – such as different types of wrenches, machinery, and toys.

However, I cannot recall an instance where an online business has been sued after creating a pretty much identical product. For instance, a particularly gregarious example of this (in my opinion), is the video game app offerings for phones. Whenever a new trend is found, a wave of seemingly endless copycats always follow.

At first, I thought it was just due to the rate of the ripoffs (e.g. the copyright holder/original creator of the genre being unable to file claims as fast as new ones pop up). However, I also see huge corporate groups such as "Ketchapp" and "Voodoo" whose entire portfolios more or less consist of slightly altered versions of popular competitors.

How is this feasible? And why does copyright law for digital services, in general, seem so much more impotent than it’s physical counterpart. Keep in mind, I am not from a legal background. Just curious, that’s all.