How are they able to do it at lower cost? Cheaper parts? Cheaper labor? I guess I’m not sure what fraction you had in mind, so I suppose in the strictest sense your statement doesn‘t necessarily mean lower cost...
The point here though is environmental impact, not cost. Does repairing your device through a third part lead to reduced negative impacts on the environment? Do these third parties do a better job of recycling their waste materials? Offsetting their carbon production? Do third party repairs lead to fewer damaged devices and longer post-repair lifespans?
Quoting YouTube is always a convincing argument... If it’s on YouTube then I’m sure it’s based on sober analysis of a broad dataset, because nothing brings in ad revenue like carefully vetted statistics.
Are there videos of third parties trying to parlay a repair into a sale? If not, does that mean it doesn’t happen? If there are 3 videos of Apple Store personnel pushing for a sale but only one video of Bob’s Mac Shack personnel doing it, which company is a bigger problem?
The question isn’t whether some Apple Store employee ever said such a thing, the question is the relative impact versus the alternatives. And remember, it’s a retail employee‘s job to make the customer happy. If there isn’t much difference in cost between repair and replacement, the employee should point that out. If the customer values the reduced environmental impact of repair, the employee should support that view.