This is simply not true. My current Notebook is a 32GB Ram equipped 13" Toshiba Portegé X-30-D, comes in at nearly 1KG and is available with a quad-core i7-8550U.
I'd just like a Ryzen 4800U version of my current machine, even if it means sacrificing Thunderbolt 3.
I think i'll have to wait for 5800U to come around and have USB4 though to see that happen. :(
Unfortunately looks like you got trolled. There's definitely no such engineering limitation. It's primarily, I think, a marketing limitation; if you want a beefier machine, they want to push you towards overall higher end equipment.
That attempts to load a customize page, then immediately 404s. This is one of those moments where I think, "JavaScript was such a poor choice on this page".
Maybe due to space, or could be power constraints. According to little Google Search, DDR4 DRAM consume roughly 1.5W per 4GB(not per module) so 32GB = 12W by itself at least at peak.
DDR4 SODIMM 32GB modules are about $150 right now so you can pop one in if you want and if your machine supports it.
I kinda feel if you really need a lot of resources you can use a cloud server or local physical box. There are lots of workstation laptops spec'd like you want but they're big, heavy and expensive.
Make one HDMI 2.0 and the other Displayport over Type-C and I'm fine.
I'd love to see a USB 3 Type-A Port aswell but that seems like too much to ask nowadays.