Experiments' solutions diverge
Collaboration between experiments breaks down, or solutions for tools and services diverges.
Multiple solutions & duplication of effort too expensive to support in constrained budgets. This particularly impacts the operational support required at sites and at CERN.
Ensure common solutions deliver and adapt to majority of use cases.
Actually there is a very psoitive effort to work on common solutions between experiments, where they recognise the need to pool effort and strategies to be efficient. The WLCG R&D projects (DOMA, HPC work etc) are all positive examples of how this is working. This must be supported via the WLCG team to help invest effort in the common solutions. The ESCAPE project is also a useful mechanism here.