Are there quality differences between in-house and outsourced Laravel teams?

Quality is not inherently higher in either model; it depends on the people, not the arrangement. An in-house team gives you direct control over hiring and standards, and deep familiarity with your business, which can produce excellent quality. A good outsourcing partner provides senior developers, code review, QA, and shared conventions that can match or exceed an in-house team, especially a small in-house team without those structures. The risk with outsourcing is choosing a weak partner with subcontracted or junior developers. Choose a senior, in-house outsourcing partner rather than the cheapest option and quality is not the differentiator; cost, speed, and control are.