I'd be inclined to agree with you if it weren't for the fact that a MTB rear disk hub can run an ISO mounted cog. Something that I did for years with no issues. Additionally, Surly, Goldtec, Phil Wood and Pauls Components all make 135 spaced fixed hubs. I'm sure there are more.
On the last point. A few companies make Aluminium street and DJ frames but the vast majority are steel precisely because they're designed to be thrown around and dropped.
I'd be inclined to agree with you if it weren't for the fact that a MTB rear disk hub can run an ISO mounted cog. Something that I did for years with no issues. Additionally, Surly, Goldtec, Phil Wood and Pauls Components all make 135 spaced fixed hubs. I'm sure there are more.
On the last point. A few companies make Aluminium street and DJ frames but the vast majority are steel precisely because they're designed to be thrown around and dropped.