Kind of offended noone tagged me in this. I still design and build molds for and sell tubular wheels.
No.
Not all tubulars are narrow. Its just that at one point in time we used to race on tubulars for road. That was at a time when we also used 20-23mm tires. People stopped buying tubulars for the road around the time that 23mm rims started coming in to fashion.
I have had 23mm tubular rims as well as 25mm tubular rims. So....seems like you're buying old used stock from road racing.
Aero - yeah it's not holding you back. The same guy that wins on a 25mm wide tubular is the same guy that's winning on a 20mm wide tubular The aero isn't hurting him unless its a pro world tour tt.