Wait. Are you saying you can put the same amount of steel blocks or wood blocks on a supporting wood block ?Weight already doesn't matter and in fact never mattered at all as all it cares about is the total number of blocks being supported. Which each block material type has different limits on how many it can support. However said material support limits are meaningless if the block doesn't have a unbroken stack of blocks below it all the way to bedrock and also note that the materials used in said stack are meaningless. In other words when making a upside down L only the top vertical block matters for determining how long the horizontal line of blocks can be.
If yes, I'll test that and if I find out it isn't true I'll send you a bill for my wasted time.

If no, how is that not the result of weight ?