Whole new form factor. Whole new light path. Whole new price point. Look at the x1300i and it’s size shape compared to a traditional lamp based model like the HT3550/TK850. Now consider that this is a ‘simple’ 1080p model without the pixel shifting apparatus required for a 4K image.
But, yes, I would not expect it will be too long before we see an LED based 4k model from BenQ in this (sub $3K) price range. But we’re still in the throws of a global pandemic that has caused plenty of issues for product development and deployment. I’m sure BenQ is working through these issues just as all companies are. We’ll get there— just be patient.