Ruslan You have to blame both Honda and Mclaren for not compromising to get there faster. Mclaren because they (Ron) insisted on exclusive deal which meant no one to compare data with, Honda because they only insist on hiring internally and working in Japan when their European base was based in the UK - which meant they could have hired ex Merc, ex Williams , ex Renault and ex Red Bull guys and worked a lot more closer to get results.
It was obvious that Red Bull and Honda would get the results more quickly given they have their sister team as a guinea pig for engine data
Something Mclaren should have learned for the future.
Its costs billions but that is because Honda had to pay off Mclaren quite a huge amount to sever as well as fund the bruising project which was in danger of dragging Mclaren down for good