Studios are not impossible. Someone has to be able to book them.
As to your question: It probably depends a lot on which 1BRs you are talking about. Glancing at the DVC Field Guide tables: A GFV Resort View 1BR goes pretty fast. SSR Preferred 1BR? You've got some time.
We booked a 1 bed @ BRV the second week of December 2026 no problem. I the ended up canceling it and rebooked an AKV 1 bed for the third week of December less than 10 months out. It’s not impossible. You might not get your first choice but it’s doable!