Honestly, they could build the same amp at a $100 higher price point and improve it considerably just looking at the photo
I absolutely understand that observation.
When you price an audio component to meet a strict price point, corners will inevitably be cut somewhere. Word of mouth feedback says that this is a good sounding amplifier despite it’s very low price (For a 300b SET amplifier). However if the building blocks (Output transformer and power supply) are good, you can improve things noticeably with better quality capacitors and tubes.
My suspicion is that the Willsenton R-300 probably has good quality transformers and power supply even at the modest price point. They probably cut cost via cheap resistors/capacitors. That’s OK these can easily be upgraded if one chooses to do so.
Charles