There are going to be 4 engine companies and many of their products will overlap. There may be areas where there is plenty of healthy competition. Traditionally in Helo engines with Mi-8s, Mi-14s, Mi-17s, Mi-24s, Mi-28s, Ka-32s, Ka-27s, Ka-29s, Ka-31s, Ka-50s and Ka-52s all potentially using the same engine there is still room for competition. The new VK-2500 engine offers superior performance, but it would be silly to think just because it offers better performance all current users will upgrade to the new engine. This means that production and improvement of the older engine still makes sense. The Russian Army is replacing Hinds with Havocs. They will certainly need new engines for the Havocs but for the upgraded Hinds they might save a little money by keeping the old engines.
With the engine used by the Mig-31 and the Il-76 the new PS-90A might be good for the Il-76 but will not fit the Mig-31. There are upgrades of the engine that improve thrust slightly, slightly improve fuel efficiency and greatly reduce engine noise to allow use at European airports where there are noise restrictions on cargo aircraft. The PS-90A is a better engine but it is about $3 million per engine. An improved basic model D30 that only costs $250,000 might still be a better choice for some uses... especially in aircraft with four engines.
With the number of new Helo engines required... not just 10-12 ton class engines like the VK-2500, but also light engines for the Mi-34 and the ANSAT and the Ka-60, and improved engines for the Mi-26 etc the will likely need a lot of factories and the work might be subcontracted out between the four main engine companies anyway simply to keep up with demand... certainly for the next few years when a lot of helos and transports need replacing.