I think the idea is by attracting new customers to EC2 via performance/price, and then enticing them to integrate with other harder-to-leave AWS services
What's the motivation behind this question? Or why do you think Amazon wants to create lockin for Graviton processors.
Note that graviton represent a classic "disruptive technology" that is outside of the main stream market's "value network". I.e., it provides something that is valuable to marginal customers who are far from the primary revenue source of the larger market.
Yes, that's the problem. Graviton and M1 are competitive with x86. What about the rest of the ecosystem? Not so much. All the promising server projects have been canceled so far. You'll have to wait for Microsoft or Google to develop their own competitive ARM server CPU or migrate back to x86.