This is like saying all things made of steel are equivalent because steel is steel, all things of made of aluminum are equivalent because aluminum is aluminum, all things made of...well you get the point.
The manufacturing process and history of a material greatly impact the materials mechanical properties an response. Different manufacturing processes introduce different defects on the microscale and cause different sorts of texture, grain alignment and anisotropy. Also, every material have various grades and chemical compositions - meaning different mechanical properties and behaviors 2025 Al is not the same as 7075-T6 aluminum and will behave drastically different but can both be purchased as cast ingots called aluminum. Cast acrylic is general term and does not necessarily mean they are the same material as therefor millions of combinations of polymer chains under similar names.
Just had to throw in my 2 cents with the materials statement.