They cannot. Linux success has nothing to do with GPL is in direct contradiction with I really think the license has been one of the defining factors in the success of Linux.
Except you left out an important bit of the OP's statement, where he/she is talking about Linux's success over BSD specifically.
When Linus was talking about the GPL being part of Linux's success, he was talking about Linux's success in general. And yeah, the GPL most likely is a big part of Linux's success.
However, if 386BSD had been freely available in '91, Linux would likely never have had the opportunity to build the developer base needed to take it from a student's neat project to a viable operating system.
[–] MaxBarraclough 22 hours ago
[–] spauldo 17 hours ago
When Linus was talking about the GPL being part of Linux's success, he was talking about Linux's success in general. And yeah, the GPL most likely is a big part of Linux's success.
However, if 386BSD had been freely available in '91, Linux would likely never have had the opportunity to build the developer base needed to take it from a student's neat project to a viable operating system.