I don't work for Onion but if I did, I'd have as many complaints about the cost as I would have about why there was only features. In the end you just have to make a decision as to what is the best combination of features and price, or you will never release anything. The market then responds and you adjust your design or you offer new models.
As a Beta tester, memory was not my issue, LittleVGL is not perfect but I looked at so many other potential GUI candidates for my specific requirements and in the end I came to the same conclusion as Lazar and Zheng. LittleVGL is a great fit for the Omega2 and if you need more, you can always build a custom board or an expansion board. The underlying technology is solid.