Being free to break things without regard for users both helps and hinders Perl 6 and Rakudo in getting to the next level.
It helps in the sense it lets the designers and implementors move more freely and quickly. The Rakudo compiler is developed in this spirit.
Breaking things hinders Perl 6 and Rakudo to the degree there's a need for many more folk who successfully deploy Perl 6 in a production setting before considering calling Perl 6 "production ready" and folk who might do so are averse to signs of excessive instability. The Rakudo Star bundle is developed for these folk.
To encourage folk to try Perl 6 in production settings, and respond to complaints about rewrites, Patrick considers it necessary to at least have explicit public understanding about managing breakages across versions of Rakudo Star.
(Fwiw I would say the Parrot team made the mistake of prematurely deploying an onerous stability policy but the Perl 6 and Rakudo teams have not.)