They’re a startup, they need to focus on the fastest and most effective way to create value for their users, today. No point optimising the product if the company dies before it starts slowing down.
I suspect the effect will be that Apple gets hate for not making fast enough computers with enough battery life, and people reluctantly spend another $1500 on a laptop after 2 years because it's too slow.
My advice to the company would be that their target device is almost certainly the base model MacBook Air with 8GB RAM running Slack, a large Excel spreadsheet, and Chrome with 100 tabs of Gmail and documents, and that if they aren't _lightning_ fast on that now they need to optimise soon, because they'll get slower over time.