Very good question. The answer is that many of these pure AliExpress dropshippers who use the standard delivery timeframes will face big problems sooner or later. Even if you offer free shipping people will complain AFTER they bought it, simply because they are impatient (even though you made clear how long shipping will take).
Especially using PayPal can lead to bigger problems here: customers wanting refunds or simply recharge because of long deliveries is something PayPal doesn't want to see. Even with tracking info this can cause you problems, without any info they will screw you even more.
So in my opinion you should think twice about starting such a "40 days delivery" shop. Customers are used to Express delivery because of Amazon etc., they won't stay calm just because you offer something rather cheap.