llms are fantastic disassembly partners, they're quite good at labeling functions from various dissassemblers -- the net losses from losing the benefits of open source , imo , outweigh the protection afforded by hiding your source code in yet another layer that is more and more easily unrolled through automated procedures.
disassembly only applies to client side software
something like nginx could arguably be more secure if it was closed source
(I am a proponent of and contributor to open source)
And isn't it also mostly a transitioning issue. Those open codebases will be constantly scanned for potential security issues and getting more and more hardened. There are probably a lot of easy wins that are going to be discovered over the next few years but it should taper out after a while.