I understand what what you are saying and don't get me wrong, SMF is great and I certainly want development to move forward. I also realize that SMF is free and the amount of effort and dedication it takes to keep it free. However, when you are running a large commercial board especially for profit, you need scalability, compatibility and predictability. It's difficult for a large forum operator to also move forward when you don't know from one release to the other what will work and what won't or how long you will have to wait for it to work.
I have a fair amount of money invested in custom designed themes, not to mention the mods I have installed including Tiny Portal which is the best portal out there bar none. Now I can't upgrade 1. Because TP won't work and there's no time frame for a new version. My themes won't work unless I now hire someone at additional expense to rework them.
So where does that lead for the future? Every time a major feature release comes out I have to completely rework everything? Maybe, maybe not, who knows? Maybe for SMF it boils down to the data model, the template system or how it was originally engineered. Again, scalability, compatibility and long term predictability. Software companies do it all the time.