I don't think it is crazy, you have to look back to the past few launches in the east.
E.g, at the time when all the condos were selling at 1.3-1.5k PSF, Pasir Ris 8 hit 2k PSF on launch day for certain stacks.
The last 2 EC launches in Tampines, Parc Central and Tenet, on launch, were the most expensive EC compared to the competitors, they were almost completely sold during first 2 months (after 2nd timer limitation lifted).
Big plot Treasure also performed very well despite all the issues like block to block proximity, single land road etc. I used to stay in Tampines, all my primary school friends bought resale there still, if you ask people in Tampines if they want to move Simei / Tanah Merah / Bedok / Eunos, they will likely say no. To them, such places are not an upgrade vs staying in Tampines. Tampines doesn't feel dense despite it being one of the largest residential estate.
Its different from people staying in SK/Punggol/HG, you tell them move to Serangoon/woodleigh/potong pasir/boon keng they will see it as an upgrade because of the proximity to town.