HDPE is an even worse choice. The basic brick uses ABS. If long-term durability were a concern, ASA might be a better choice but it costs 50% more. Changing

HDPE is an even worse choice. The basic brick uses ABS. If long-term durability were a concern, ASA might be a better choice but it costs 50% more. Changing it to be something else would just cheapen LEGO to something that wouldn't permit intergenerational inheritance.