Your comparisons are out of context.
It is difficult to make a comparison with 4E and 5E because their systems don't utilize the same rules between player characters and NPCs.
It is a little easier in 5E if you compare a 1st level fighter to a Guard NPC character. In such a comparison 1st level 5E characters start at more capable than a typical town guard or soldier.
3rd edition 1st level characters are similar due to comparing a player character class to the npc classes (which were lower in power to PC classes). So a 1st level fighter would be superior to a 1st level warrior by that nature.
OSR games, 1st level characters are Veterans. There is a reason they fighter class has a level title. If you compare a 1st level fighter in B/X or similar to a typical mercenary or 'Normal Man' type, they have superior hit points, better attack and saving throw progressions. A 1st level OSR fighter is a veteran soldier who has lived through several battles and is hand above a typical soldier.
I don't understand the idea of OSR characters being barely trained newbies. The farmboy with a sword would be an unclassed "Normal Man", not an actual player character.
Your error is that you are comparing the capabilities of a 1st level OSR character to the capabilities of a 1st level 4E character (or any other edition), which are different games based on different power levels.