None of that reasonably characterizes the reality at all, only what some might fear. In practice, any distribution is suitable for any ordinary purpose, and only relatively uncommon hardware lacks drivers out of box. Linux supports a wide variety of applications just fine.

Common software is generally provided by your system package manager and doesn't require adding any repositories. In the cases where you need to rely on one of the various third-party packaging solutions you assume the same risk that is normalized for every software installation on Windows. A curl | sh invocation is not fundamentally less secure than running an .msi installer.

Old forum posts don't actually 404 and you will practically speaking never have to go back that far, and people don't give you broken links, and if the old information somehow really disappeared or became invalid you could just ask again. And no, even in the Arch world they don't give you a run-around intentionally; they just expect you to demonstrate basic problem-solving skills and not waste others' time.