Were I Larry Wall, I doubt that Perl would be as successful a language as it is.

That said, your comment about the license suggests a fundamental misconception on your part. Perl is a very successful language. Perl is free and open, and encourages the same for its users. These two statements are not independent.

Trying to give Perl a restrictive license would kill the goose that laid the golden egg. Many of its most valuable contributers would be unable or unwilling to contribute if it was a proprietary product. Many of its most capable and most valued promoters would be unlikely to use it if it was a proprietary product. Attempts to encourage the user community to share would fail if the language itself did not set an example. (Do you think Larry could write CPAN?)

When you see the goose that lays golden eggs, don't try to figure out how to get the gold in the goose. Rather start by figuring out its diet...