I think it’s a syrian initiative, the reality is they have all been fighting for 14 years. There are people there who have fought in Iraq (al-qaeda or ex al-qaeda) in Afghanistan, in China. There are many who were battle hardened before Assad started murdering his own people. The Turks knew about this, they put the kibosh on the first suggested date and then the Syrians ignored them at went ahead later.
The Syrian army just collapsed. This isn’t the west and I think it’s a weird thing westerners suffer from, the belief they are somehow at the heart of everything. Israel eroded the IRCG and Hezbollah in Syria plus both were oriented towards attacks on Israel, the Russians were moving resource into Africa and Ukraine while Turkey increased it’s influence through the SNA. The amount of effort and investment by Assads allies is quite different from when he went mental.
The situation has not been static all this time, even if the west wasn’t paying attention. The reality is for the west the best thing would have been Assad to stay in place and Syria to be contained vs an open ungoverned space run by Jihadis. Hell even for the Israelis a weak Assad which allowed them to bomb Hezbollah and IRCG has been better for them than the prospect of a neighbour run by Al-Qaeda. Which is why they are bombing the living daylights out of any place with weapons , aircraft, chemical weapons.
No-one knows what Syria will look like in a year, the uncertainty is not great for the west or Israel, they are all scrambling to get a handle on the situation and the implications. Turkey thinks it’s expanding it’s sphere of influence, I expect them to be kicked out sharpish when things settle down.
The Syrians got rid of Assad/Hezbollah/Russians and Iran with a bit of “help” from Turkey and Israel and the inattentiveness of Russia and Iran. The west has been sitting on it’s hands for 14 years. It didn’t wake up one day and think “ah shit, we forgot to liberate the Syrians”. They did it themselves.