You assume I'm not using all the other tools, and you're wrong. It's rather insulting, quite frankly, to be accused of being so unimaginative.
So, I just did a quick test. I went into Hyrule Castle, got a brand new Royal Broadword ("Attack Up" version, 49 damage). I saved, then took it out into the world and hit enemies with it. 32 hits. I re-loaded and did it again to make sure. 32 hits - on enemies, not shields, rocks or trees - that's it, before it breaks. The first time, I just ran south from the castle. I think I killed 3 Keese, one Windblade guy, and 5 Bokoblins, one blue. The second, I warped to the Bottomless Swamp in southeast Hyrule Field and killed 4 Bokoblins, 3 of whom were bow guys and went down in one hit, one Silver Moblin, and knocked a Silver Bokoblin into the mud. That leaves several enemies in that single location alive.
Does that sound reasonable? 32 hits, for the 2nd best one handed sword in the game, outside of the Master Sword itself. Be honest. You really don't think that seems low?
Royal Broadsword have 36 hits, and are the 6th best one handed swords for both attack power and durability. (7th for durability if you count the Spring-Loaded Hammer)
3 Keese - It is safer, easier and faster to kill them with one bomb.
Yiga Blademaster - They always drop their Windcleaver, and can drop Mighty Bananas. Use them.
5 Bokoblins - Most of them have weapons, the dragonbone variants are more than decent. Use them.
No way it broke after that, especially with a 49 damage one.
4 Bokoblins - Same as above.
1 Silver Moblin & 1 Silver Bokoblin - Silver variants have a lot more HP, and they always drop good weapons and minerals to make the champion's weapons) Use them.
Oh, and all of them drop loot you can sell to buy arrows.
So it's 6 weapons in each case, including one where you use your weapon for no good reason and have some durability left, and another where you defeat 2 silver monster.
At max you can only carry 19 melee weapons and 13 bows. And yet you call the 6th best one handed sword allowing you to get 6 new weapons, not "reasonnable" ?
He might not be saying you are playing wrong, but he is just being nice. You are playing as wrong as your knowledge of the game is.
If a game gives you limited ressources and you use them carelessly you are the problem, not the game. Anyone playing correctly will have a inventory full of good weapons without even trying.