I wonder whether the problem with cycling gear is that the pros are usually on the diminutive size, so everything is based on making stuff for them.
I find Biemme and adidas do "real-world" sizes - I'm 187cm tall and around 85 kilos, and take an XL in both adidas and Biemme (although admittedly an L in most street clothes).
Whereas I bought a jersey from a French online store and it took me a almost three months to get a jersey that fit, as each order had to be sent back and the next size ordered from their supplier, with an extended delay each time. And in the end I had an XXXXL - which is absurd.
Even chest measurements don't work. What one company claims fits a certain chest size can vary, as well. I ended up with a jersey from one company that flapped around on me like a sail.
It would be a lot easier if they all put proper measurements based on the actual garment - ie armpit-to-armpit, across the shoulders, length down the back, arm length... That way you could dig out one you already own that fits, and measure it for a direct comparison.