Diki,
A basic Wersi Abacus is all most people would ever need to do what they want. I wanted 76 keys and foot pedals so I opted for the Duo Pro version. The Abacus is around $7,500.00 USD. The Ikarus is also available and it has 76 keys and costs around $5,500.00 USD. One could hardly buy a Tyros 2 and a nice car for that kind of money.
I think you are seriously missing the point when it comes to the Wersi and why they charge so much for their products. The build quality and features rival any arranger made (all metal construction with wood sides, high quality TFT touch screen, lots of real time buttons and sliders). In addition the user interface is so well laid out you won't find another arranger that has so many features that is as easy to use. Until you've used one you won't be able to understand this (Wersi owners know what I am talking about).
Even if you bought the fanciest computer made, loaded it with GB's of RAM, VST's, audio software, and more, it would still not operate like the Wersi. Wersi has their software setup to operate all the features with such ease a small child could run it. To do this required Wersi to write extensive code and integrate VST's into their GUI, all that takes time and costs money. I would hardly call the Wersi incrementally better than a computer running VST's as there is simply no comparison in how the two operate. Wersi = Easy. Computer + VST's = Pain in the ass! Sure a computer system can work great but intuitive it's not.
Lionstracs can and will cost Wersi sales in the near future but not until Lionstracs GUI is as easy to use and factory sounds are on par. Right now Lionstracs offers nearly everything the Wersi has to offer at about half the price of a basic Wersi Abacus. Once Domenik improves the Mediastation sounds and fine tunes the GUI, Wersi will have a much harder time selling instruments. Still the Wersi does have some hardware features like dedicated drawbars but the Mediastation has programmable sliders that can act as drawbars.
It seems that Open Ended Instruments aren't for all people and that's fine. As I aid before, not everyone can afford them, nor do some people need the extensive features. For those of us that do the Wersi and Lionstracs are a great option to the basic arrangers offered by Yamaha, Korg, and Roland.