If having worked in UNIX, Plan 9 and Inferno (and saying "having worked" is quite an understatement), having designed and implemented several programming langua

If having worked in UNIX, Plan 9 and Inferno (and saying "having worked" is quite an understatement), having designed and implemented several programming languages (Alef, Squeak, Limbo, Sawzall, Go, ...), and having been an important part of Bell Labs and Google during their respective peaks is considered lack of experience in systems programming, what on earth would you consider as enough experience?