It’s no so easy anymore as a blanket price cap. There is now limits on what components can be and they must be available to all teams, not sure when all this kicked in as I think it is a phase in, with backlash from teams such as Kawasaki.
Ducati has been strangled to allow them to use a 1200 cc engine, and must have standard components in the engine hence the special R’s of the past. The 1000’s have had much more flexibility to say the least.
This will all change when Ducati goes to WSBK with a 1000 4 cylinder, one of the reasons for doing it.
Also homologation of specials has changed which may mean we will see some special bikes being made by all manufacturers
But the rules are constantly changing so who knows
All very complicated
Here is some of the updates for rules for 2018http://www.worldsbk.com/en/news/2018/New+season+to+bring+new+rules