I don't know who else was involved but it certainly wasn't just von der Leyen, this was complete institutional failure.
Probably as well the most effective Brexit propaganda you can imagine.
Of those suppliers, only AstraZeneca acted with bad faith to excuse non-delivery. The other suppliers - having the sense to understand Covid is a global problem, not a national one - didn't.
The UK then used its gamble on an untested schedule - the gap was originally supposed to be weeks, not months - to turn vaccination into a propaganda exercise.
Meanwhile the British variant, which appeared because the UK failed to lock down properly in the first place, is still causing tens of thousands of deaths across the EU.
Institutional failure you say? Indeed it is - on the British side. If the UK had acted rationally and responsibly a year ago, there would have been no need for vaccine nationalism.
Changing the vaccination schedule in the UK, on the other hand, was an informed gamble that - based on what was known about the vaccine at the time - would likely result in much fewer people dying and being hospitalized than sticking to the original, basically arbitrary, vaccination schedule.
Also, blaming AstraZeneca for the EU falling behind the UK in vaccination is 100% pure propaganda. As far as I can tell, at this point their vaccine deliveries to the UK are about as far behind schedule as the ones to the EU, and the UK is a lot more reliant on AZ vaccinations than the EU. The EU just didn't order enough - their initial AZ order was about the same size as the UK one, for a much larger population, meaning they ended up with less production capacity relative to their population than the UK. The reason it seems like the UK vaccination scheme is going to plan is because the UK contract had contractual clauses with teeth requiring AZ to promptly notify them of how much they were actually going to deliver once they had their plants up and running, and the UK's plan was based on the actual delivery schedule. The EU... didn't. At all. I don't think they understand this even now, judging from all the conspiracy theories about how the yield problems are an excuse and AZ are really just sneaking off doses to the UK.