They tried that since 2014. All they got was lies from the US and the EU. In that respect, Putin has admitted he was a fool for believing them. It all could have been avoided with a litle honestly, something the West does not have. For instance:
“They tried that since 2014.”
Yeah, those “green men” all decked out in full battle rattle that descended on Crimea in the middle of the night were just “diplomats”.
Most of Putin's time and speeches are actually reports to various bureaucracies he is required to report to.
Western Media has mislabeled Putin's reports to various bureaucracies and legislative bodies as "Speeches" unilaterally advocating policy when they are reports discussing policy.
Putin does request legislation and policy changes, however he's not guaranteed to get them, and he is required to discuss them with the relevant bureaucracy.
This bureaucracy is powerful, is not going away, and neither is the Russian Federation equivalent of State Department.
That's why Russia uses Diplomacy and Bureaucratic management so much.
And it probably hurts them some.