It is doubtful BETHESDA is going to bring ES6 IN 2026 simply out of scheduling.
First, they have to get STARFIELD out.
Then there's milking it with DLC and "creations".
That is going to keep the staff busy for all of 2024.
Are they getting ES6 (which reportedly hasn't nailed down the main quest) out in 18 months?
Nope.
Second, look at Microsoft's schedules: STARFIELD 2023, AVOWED 2024, FABLE 2025. 2026? OUTER WORLDS 2 or CLOCKWORK REVOLUTION. The loser gets 2027. ES6 gets 2028. Or are they going to do two RPGs in the same year? Not likely.
Third, 2028 gives Bethesda time to incorporate GPT tech into their NPCs. After all, if modders are doing GPT NPCs in Skyrim now, Bethesda has to match or better that for ES6 and beyond.
And, fourth, 2028 is the expected realease of the next gen consoles. What better launch than to send it out with ES6? Morrowind, Oblivion, and Fallout 4 all launched shortly after the first three XBOXes and because they needed graphics cards that cost more than the consoles, they goosed sales early. With better control of both schedules, MS can send the next generation out at the same time.
No matter how you look at it, 2028 fits.
Actually, the real fun is going to be how MS slots their shooters if they do get ABK.