I have been riding zwift for almost a month now and i would like to see more bike brands offered as a main bike. It would be a good idea to offer 2 bike options to start
zwift carbon
personalized bike in my case bh ultralight
in turn you could charge the companies to just basically for ad placement.
do the same with the wheels. I think the experience would be a bit better if my virtual bike resembled my real life bike.
If you look through this you will see you will unlock more bikes as you level up and complete challenges: http://www.titaniumgeek.com/cycling/zwift-user-manual-unofficial-running-updates/
I’m kind of curious why a steel bike is considered an upgrade. Don’t know too many people who get excited about replacing their carbon with a new steel bike 
Is there some difference/advantage you get riding it that I didn’t notice? Granted, I only tried it for a few rides and suffered an injury setback not long after, so maybe there is something I missed. Looking forward to getting a Madone, though!