we think you'd be best with a bigger team with a better support network
Sounds like they think you're not independent enough for the position. If it is a small team, they might need someone who can immediately start being productive, while they think you will need more coaching to get up to speed.
No need to drag any disabilities into this.
It is more of a "For typical cards, expect very competitive options from AMD. If you want top performance, buy Nvidia."
In theory it allows them to focus more on the cards that actually get bought, and thus they could make those cards better products.