market has hardly anything to say about it. The fact is that projects being difficult to compare are also difficult to draw conclusions upon. I actually have made a comparison of two projects running on two different platforms and using two different (*) paradigms - my corp just bought another corp where exact same thing has been done already but as said on other platform. The one had 300% higher cost than the other. The thing is - when I proposed to have a look at the reasons and do root cause analysis I was ignored. I took from this experience that this is a religion not a management practice.
* - It is often proposed that there are two approaches: waterfall and agile. I have not seen a fully waterfall project in my long working life and I took part in projects of 10k people lasting up to 2 years. The fact is you need some rigid planning and the planning and deadlines many months or years in advance because somebody has to budget the project and needs some sort of idea of what is feasible. Even agile teams do that or they overrun the available budget and then fail. These big projects had what appeared waterfall - they set deadline 2y in advance. Yet the project planners were flexible and the planning allowed to build a huge robust, flexible and powerful system that was delivered within an accepted deviation of budget and time. the actual development teams working on particular items were doing their iterative design & test and acting in an agile way if (from their perspective) external part necessary for test was delayed. I have seen similar in much smaller but in agile term massive (~100 people, run for a year) teams/projects.
After all these years I have made following observation: the development paradigm and chosen technology have less to say about possible success than the qualifications of the team. Good team with good leaders can achieve a lot. Not even best practice and good conditions to execute a project will help if team does not know how to make, deploy, revise and if need be modify decisions. Whether they do it during grooming meetings smoking joints or there is an uniformed drill instructor shouting on them is relevant because wrong are to the team and project what the tools are for the job - you just need the one you can work with.