Without Full Transparency, A Single Standard For Ticket Distribution is Pointless
Taxpayers are spending at least €73 billion per year on EU Rail and 64% of passenger rail operations being subsidised (EU Commission, Rail Market Monitoring Report, 2022).
Therefore, EU citizens should have the right to full transparency; one single standard for distribution helps, but there must also be regulatory action: All passenger rail options sold at All rail ticket vendors. 
Otherwise, a single standard is pointless – the EU risks spending a lot of time and money on it, but in effect there will be… No Change. 
Across Europe, there are still many reasonable rail journeys that cannot be booked. For example, there is an hourly, cheaper connection between Brussels to Cologne on subsidised Public Service Obligation (PSO) trains, covering the 224 km distance in around 3 hours. 
However, you cannot search or book this connection easily at the same ticket vendor – there is no One Stop Shop. Instead, the traveller has to put the journey together in separate bookings – and very few know that this is even possible.
There are plenty of similar examples, such as between Paris and Barcelona.          

▶  Fact: ticket vendors should not be hiding existing rail services  
The Solution is twofold:

1. On the technical side, there is already a ticketing standard that enables full transparency: Transmodel NeTEx. It must be deployed through the next revision of the Telematic Application for Passenger Service TSIs.

2. On the regulatory side, the upcoming EU Multimodal Digital Mobility Services (MDMS) initiative must ensure that All Rail Services Are Shown and Sold At All Rail Ticket Vendors.
ALLRAIL Secretary General Nick Brooks says: “It is crucial that technical and regulatory issues regarding ticketing are dealt with at the same time. Otherwise, many existing rail services will remain hidden, and the whole effort will be pointless.