Why did american indians occupy alcatraz island in 1969?

Because according to the Treaty of fort Laramie between the the american government and the Indians all retired, abandoned or out-of-use federal land was to be returned from the native people that it was taken from (in this case the Lakota tribe)

following type of cultural development caused people to want and buy new products on the market :

industrialization

Why do you have to ask such hard questions.