Look at the options... start adding memory, start adding hybrid SSHD's (which you'll need to be able to practically fill the RAM quickly) - it all adds up.
And don't forget, the included VSTi's and effects are not exactly TOTL. Make a list of all your favorite libraries and VSTi's, and the cost goes up another few tens of thousands. Vienna Symphonic full library, $6000 or so (who's going to want this and NOT want the best sounds for it?). NI Komplete Ultimate, $1000. Omnisphere, $499. Ocean Way Drums $1795. ProjectSAM True Strike / True Strike 2 Bundle $738. And that isn't even scratching the surface. A full Waves plug-ins license is upwards of $5000.
Going soft is VERY hard..!
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An arranger is just a tool. What matters is what you build with it..!