There are quite a number of vectors that are activated similarly regardless of large swaths of the implementation. For example: if you're hosting a self made s

There are quite a number of vectors that are activated similarly regardless of large swaths of the implementation. For example: if you're hosting a self made shopping cart versus an open source/commercial product, there's probably a higher risk of being vulnerable to SQL injections. It's conceivable that open source and commercial offerings have been beaten on more and as a result hardened against more attack vectors. Of course to your point, it means that you're not vulnerable to a zero day that impacts many deployments. I imagine the shops that made their own logging library were quite pleased with themselves when the log4j vulnerabilities came out. My point being that it's not a simple calculus, and it's really hard to evaluate the relative risks of one versus the other. It's probably best to look at the cost of implementing and maintaining security through obscurity and using that as a litmus test for if it's reasonable or not. Running something on a non-standard port has a very different cost than making your own operating system.