Open keyboards are not a 'concept'... they are a tool. A tool for making music. And, compared to a closed arranger, a fatally flawed tool. The truth is, the VAST majority of arranger players are more interested in MAKING music, and not spending their entire life programming a blank slate just to achieve the functionality that a closed arranger gives you from the day you buy it.
While there may not be as MUCH possibility for improvement, it's not like open arrangers are unique in being possible to improve. Most closed arrangers have a sampler, should one choose to use sounds the manufacturer doesn't supply, and most arrangers have all the tools you need to make your own styles, should you WANT to... But they don't set themselves up so you HAVE to.
And that is why they dominate the market. There is no lack of understanding about what an open arranger is. In fact, everybody is only TOO aware of what they are... and that is why the vast majority give them a wide berth, me included.
Let's face it, once you decide to use an arranger to make music, rather than through composing something and creating SMF's or audio backing, or strictly just recording the old fashioned way, you have acknowledged you are looking for an EASIER path than the traditional way. That's what makes them so popular, even with players that CAN make high quality productions by sequencing and recording audio. And, once you acknowledge that people are looking for a path that IS easier, giving them a pretty much blank slate and saying 'Have at it!' completely misses the point of what they want.
No-one is saying that a well voiced and styled arranger is the END of the line. There are quite a lot of us here that take our arrangers past the state it comes in OOTB. But given a choice between STARTING with a great sounding, well voiced and styled arranger and going on from there, and having to work for what seems like an eternity to even get CLOSE to what is the STARTING point for the rest of us, seems to me most of us here make the PRACTICAL choice.
I keep coming back to this, but it STILL seems that those MOST invested in preaching to us how we just don't 'get it', we don't understand the 'concept' and all the other buzzwords intended to prove their OWN superiority at having recognized the future before the rest of us saps, they are the ones that consistently fail to provide arranger examples to illustrate their point. If it IS so easy, (or even if it is hard!), just WHERE is all this music that YOU have made? Or are you, as seems most likely, STILL trying to coax even ONE standout style from your efforts?
As I said, if any of you have achieved sonic nirvana out of your open arranger, market the data. The line will go round the block once you get full closed capability out of an open arranger to add this functional ease to what would be a GREAT keyboard once it contains it, but isn't until it does...
My check book is ready. How are YOUR styles?