The power supply is limiting the market from my perspective. I have one item with an external power supply.What's bad about the power supply? Topping has been using such power supplies for a few years now and we've never heard anything negative about them. It can't be that bad, the measurements speak for themselves.
And nobody is stopping you from connecting a different power supply, it's actually very easy.
A larger case with a built-in power supply would make the device significantly more expensive and require additional checks and tests, which would also have to be paid for by the buyers. At the same time, the higher price would significantly reduce the number of units sold, meaning that the total costs would have to be spread over far fewer devices, which would again make the device significantly more expensive.
NEVER AGAIN!
I'll happily pay more to not have an external power supply.