Yes, Germany's Turkish community largely traces back to Gastarbeiter recruitment in the 1960s/70s.
But since 2010, Germany alone received 850,000 Muslim migrants, with 86% of refugees coming from war zones like Syria, Iraq and Afghanistan.
Between 2013 and 2019, nearly 70% of all refugees in Germany were Muslim. Across Europe, large Muslim communities in Sweden, the Netherlands, and elsewhere originate from Iraq, Syria, Afghanistan and ex-Yugoslavia, not from guest worker programs.
The Gastarbeiter framing erases the millions who came because their countries were destroyed by wars the West participated in.
"The Gastarbeiter framing erases the millions"
Don't try this newspeak at me. I said quite clearly that majority, not all, European Muslims are descendents of Gastarbeiters.
Or OK, lets use your newspeak. When it comes to framing, your framing of the wars in the Middle East is that they are completely attributable to the West. Do the locals have no agency? Didn't they engage in wars prior to rise of Western power? Is the Shi'a-Sunni split a Western plot? Did Islam spread by completely non-violent means?
Muslims are humans, and as such perfectly capable of waging wars on their own.
In 1990, both Syria and Türkiye were roughly comparable developmentally, with HDIs of 0.563 and 0.598 respectively. Yet by 2000, Türkiye's HDI significantly outpaced Syria's (0.669 versus 0.587) despite Turkiye going through severe political, social, and economic turmoil. And by 2010 (the eve of the Arab Spring), this difference in HDI was significantly exacerbated (0.750 in Turkiye versus 0.661 in Syria). Furthermore, both Turkiye and Syria participated in the Gulf War and didn't participate in the Iraq War.
The key difference was the billions the Assad regime spent on it's occupation of Lebanon from the 1980s to the 2005 Cedar Revolution, backing the PKK to antagonize Turkiye, and embezzling into slush funds the Assad family now uses to finance their life in exile in Moscow and Dubai. Meanwhile, during the same time period, Turkiye spent similar amounts building a welfare state and investing in expanding the social safety net and investing in infrastructure.
And other Muslim majority countries that were comparable to or significantly less developed than either Turkiye or Syria in 1990 such as Algeria (0.593), Indonesia (0.526), and Iran (0.613) were able to either catch up to Syria by 2010 such as Indonesia with an HDI of 0.667 or outpace it such as Algeria with an HDI of 0.721 and Iran with an HDI of 0.756 despite either starting from a lower base and going through an economic collapse in the 1990s (Indonesia), going through a devastating decade long civil war throughout the entirety of the 1990s (Algeria), or rebuilding after a decade long war and sanctions (Iran)
Even IRAQ, despite starting at a significantly lower base in 1990 (HDI of 0.497) was able to roughly catch up to contemporary Syria by 2010 (with an HDI of 0.629) despite the Gulf War in 1991-92, the sanctions regime, the Kurdish insurgency, the Shia insurgency, the Iraq War, and the subsequent Iraqi Civil War.
Fundamentally, the Assad regime mismanaged Syria, and it's lack of institutions outside of the Army and the Baath Party along with existing social fissures due to Hafez al-Assad's brutal repression of Sunnis in the 1970s-80s meant Syria's collapse was a question of "when" and not "if".
If institutions are robust, development is compounded. If institutions are weak, development slows down and fissures in society grow larger and larger leading to a breaking point.