It should be perfectly possible to come up with a collaborative approach to this. The current system clearly doesn't work very well, with the Pacers (and I would also argue 150s) staying in service for longer than they should, and on the other hand units (EMUs) which are fairly new or have recently had extensive refurbishment going off-lease before they should. These issues could be avoided with a coherent cascade plan, which could include broad specifications for new fleets required, and ROSCOs could then offer what they thought met those specifications via a tendering process.