Allegedly a short (1/2" long?) nick cut through the outer skin where the blade starts cutting helps circumvent the hard skin issue. Presumably because the blade is able to cut immediately and pulls the hard skin away in thin layers with the chips. If the blade merely comes down on the skin it skates around until the skin is worn through. Which is very hard on the blade.
Breaking in a new blade considerably extends its effective life. Unfortunately following proper break in procedure is pretty much impossible with those saws.
Feed rate and pressure is also an inherent problem with those small hobby saws. The usual spring thing is somewhat non-linear and generally doesn't allow enough feed.
Bottom line is you are asking a boy to do a mans work.
If you have space seriously consider an older, relatively inexpensive, power hacksaw for that sort of stock cutting. My £100 Rapidor is very effective and would soon have paid for itself in reduced blade replacement costs if I did the amount of heavy cutting you seem to be doing.
Clive.