The s2 is only a viable option if you run it as it is in the box. If you want to get serioud with the upgrades, just buy a prospec. Lots of people buy an s2 for parts. At rc marts $84 that's viable but $129 stateside not so much.
Of course more shipping ect. Everything is relative.
An r1 pro and a few spares is a great way to get started in tc. S2 is fine in the hands of a decent driver but I actually wouldn't recommend it for a new person. Too many prep things needed to be done to make it its best.
But they have undoubtedly made a killing on the s1/2. No other reason to release a plastic version before a new full version.