I am currently shopping for a road bike and have questions about current frame designs. My height is 6'3" and decade(s) ago I always liked frame designs for which the top of the seatstays joined at the top of the seat tube, along with the top tube. A purely horizontal top tube was also more aesthetic looking as well. Nowadays, frames look like a squashed parallelogram, which is likely due to weight-saving considerations -- since less framing is required(?)
The question is: why do almost all seatstays now join in the middle of the seat tube, which places more stress on the top of the seat tube? Further, for a taller-heavier person, the seat post must be elevated, causing more stress on the top of the seat tube. I think if the seatstays joined at the top of the seat tube, there would be less stress on the seat tube when the seat post is highly elevated.
In light of the above considerations, does anyone manufacture a more parallelogram frame that's not squashed, and with seatstays that join at the top of the seat tube, with a horizontal top tube?