I think the replacement of Meccano by Lego is directly responsible for the decline of civilisation. Like replacing tea with coffee.
I do have some reasoning behind that, directly connected to what you say. To get anything but the most basic 'traditional' Meccano model to work, you have to think. The instructions are basic and often incomplete. Manual skills are often required above and beyond simply cliking things together.
I will admit I recently visited the Lego store in Liverpool and was highly impressed by the variety of stuff they now sell, but none of it requires that practical engineering input that Meccano requires, not does it have the incremental levels of difficulty that was inherent in the old Meccano progressive set marketing. For those who don't know, you started off at maybe 5 years old with a set '0'' - note they started with zero, a lesson in itself - and progressed, if you were lucky and your Pa was was rich, to a number 10 set by the age of ca. 15, just before, in those days, you learned what girls were for.
To declare an interest I have two Meccano 10 sets and most of a third, plus loads more specialist sets like the 1960's Elektrikit that let you assemble your own solenoids etc. I even have the modern robotics set that can be applied to models going back to the 1920's. not that the current manufacturers know or care.