There are valid reasons but I think the performance angle is the weakest argument to make.
I highly doubt that. Path traversal is one of the most optimized pieces of code in the Linux kernel, especially for commonly accessed places like /bin where everything is most likely already in the dentry cache. For the script with a shebang on the other hand it first has to read it from disk (or the page cache), then parse the path from it, and then do a path traversal anyway to find the referenced file.
Those that exist today would, but no kernel would have to work like that.
Once you've agreed that monolithic kernels have merits, you've accepted that the kernel can do whatever it wants to make this efficient—including being complicit in this scheme and leapfrogging over most of what you just described.
That's a pretty weird argument. "Yes, what you say is completely correct, but let's imagine a world where you were wrong."
We have what we have, today. We should form conclusions and make decisions based on things that exist, not on things that we might dream up.
Aside from that, it's against the rules here to those kinds of fake quotes. (And even if it weren't against the rules, it's obnoxious and disingenuous on its own, so just, like, you know... don't do it.)
What part of the guidelines are you referring to?
Also, despite the quotation marks, I don't think they mean to quote you. They're just rephrasing you as they understood you.
Coincidentally enough, I've just done that too in another comment:
And I didn't mention the guidelines (i.e. newsguidelines.html). On that note, though:
> the site guidelines[...] aren't a list of proscribed behaviors but a set of values to internalize. I'd say "Please respond to the strongest plausible interpretation of what someone says, not a weaker one that's easier to criticize" covers this case pretty squarely
(from <https://news.ycombinator.com/item?id=15892014#15893789>)
See also:
<https://news.ycombinator.com/item?id=38688831#38690517>
plus lots (and lots) more.
Finally, symlinks can be relative, while the solution you proposed is not. This is particularly useful for distributing software, e.g. distributing a tar file with the busybox itself and their symlinks.
In fact, you don't even need symlinks at all: you can even have hard links, that could even save disk space on embedded filesystems, that are readonly images anyway.