You seem to put a lot more trust in the networks than I do.
Your example of them taking years to agree the PAC mechanism (number portability) is a good example - why would they hold back on that for so many years if they were on the side of the consumer.
Similarly roaming (GSM (presumably other systems) routing calls back via your home network), it's not necessary technically, but otherwise it makes it hard for your home network to bill you while you're abroad. Contactless payment is the same, they're struggling to find excuses why the network should get a slice of the fees.
Don't get me wrong, I understand the dilemma that consumers aren't willing to pay what it actually costs to provide mobile bandwidth, so they have to charge extortionate (compared to the actual cost) fees for services we are willing to pay for, but I don't think virtual SIMs would be bad for consumers at all - as long as there's a standard.
I travel a lot, but don't spend enough times in many countries that it's worth me owning a SIM there, but if I could just reflash a virtual SIM when I arrived, that would be much more practical... or the threat of actual competition might encourage the networks to make roaming work in a more rational way.
I also suspect you're wrong about the SIM size too - though I have no technical knowledge in that area - the space saved is pretty substantial compared to the size of the device. Also, if it was really an attempt at lockin, they would have made it electrically incompatible with the fullsize SIM and mini SIM.