Don't really agree, it has been accepted far more readily in other countries, generally where it has gone wrong has been where they have gone with a cut price version, the old adage you get what you pay for, or the bosses have messed around with the protocol or implementation (i.e. England). How much controversy can anyone remember from the Euros, World Cup, or UEFA competitions? I'm struggling to think of any, and that really points at the PGMOL implementation, as well as that in other countries where it has had serious issues.
I do think Howard Webb will get it right eventually. Don't think we should forget he took over from a regime that changed the bar for VAR almost every other weekend, that must have been impossible for the officials. I suspect as the legacy officials "age out", and the panel becomes almost full of referees that have had VAR since they started it will improve significantly.
I'll also add that a major problem in England is the massive influence the EFL have on PGMOL. That needs to stop, either PGMOL needs to become completely independent of the EPL, or disbanded and the management of officials moves back to the FA. That isn't just in relation to VAR, but it certainly plays a part.