Originally Posted by
psychokilla
For context, for my last trip, I found that eco+ on Qantas was comparable in price to eco/bus on Emirates. I wouldn't have been able to do eco/bus on Qantas because of that eco+ class, but it was pure accident that I came across the Emirates price because they wouldn't have been an airline with which I'm familiar.
I just need to be more aware of these options when booking long haul
I don't really understand your logic. Qantas offers premium economy which is a separate class of service between economy and business and these aircraft are 4 class.
Airlines price their fares for each cabin for each route, with the price determined by many factors including other airline competition and prices.
The fact that Emirates economy/business (I'm assuming that is economy one way and business return) is a similar price to Qantas premium economy return, but that economy/business return on Qantas was higher isn't specifically because Qantas offers premium economy, but more that most Qantas longhaul discounted fares do not allow you to combine economy with business.
Airlines with premium economy don't price their business class higher just because they offer premium economy.