I think it all boils down to the skins market personally, people open 30-50 million cases a month (probably done that in the last few days though!) which is such a huge revenue stream for Valve. They've had to transfer skins over to the new weapon models, and I expect they'll release a case/operation in due course and I imagine that will only work on CS2.
Back when CS:GO was released lots of players (pros included) almost refused to move over because CSGO wasn't as polished as 1.6/CSS, some even tweeting saying CSGO would never be as big as CSS
I think moving everyone over will lead to the game getting polished much quicker as well, as there will obviously be more data.
As for missing game modes, the Arms Race maps have been teased in videos and on Steam, so I would expect them to be releasing at least that at some point soon. Matchmaking/Competitive was always far and away the most popular mode though, so makes sense for them to focus on that first, especially as that's what the pros play.
Can't help with the transfer of keybinds sorry mate, but jumpthrows are now a "skill test," simple let go of your mouse button at the top of a jump and you will get a sound queue to know that it's been completed successfully. Super easy, don't think i've failed one since the start of the Beta.