Well, yes and no. Yes, the fighter may have had less hit points (depending on the luck of the dice) but, let's not forget, the orcs and kobolds are hitting far less often and far less hard.
Less often = crapshoot I mentioned.
A 1e fighter at 1st level isn't too put out to get an AC of 4 (chain+shield is hardly a difficult assumption. Banded is quite possible for an AC of 3) and the orc or kobold had a THAC0 of 19. That means the orc's only hitting about 25%. If the fighter has a dex bonus, that goes down by 5% every point of AC bonus.
Dex bonuses didnt start kicking in until you had very high attributes... people used to 4e with 12 actually meaning something different than 10 would be confused by having to wait till the very high end (attribute values 15+) to see actual bonuses.
The die rolls during character creation were also an incredibly significant part of that crap shoot. It was very easy not to have Dex on a fighter high enough to boost it.
A 16 Dex (again, not a huge assumption IME) is worth a -2 AC bonus, and now the baddies are only hitting about 10-15% of the time.
And, let's not forget, the average damage for an orc is only 4 points.
Compare to a 3e orc, where his effective base THAC0, because of his strength, is 16 and the AC of the fighter at 1st level isn't all that different with a 16 or 17 AC being about average. That means (in 1e terms) the orc is now hitting on a 12 or a 13, instead of a 16 or an 18. Plus, our orc is now doing an average of 9 points of damage per hit.
IOW, the orc is hitting twice as often and twice as hard.
I'm not sure I agree with the idea that 1e 1st level characters were these fragile little flowers that folded if you sneezed at them wrong and 3e 1st level characters could waltz all over every encounter. IME, 3e combat was far more lethal (barring save or die) than 1e. I rarely killed PC's due to hit point loss in 1e. In 3e, it's ridiculously easy to obliterate a PC at just about any level with an EL=Par encounter.
Well I can't compare 3e ...but it was indeed also ridiculously easy to obliterate PC's if you werent blessing them with super extreme attributes in AD&D at level 1 (and the fighters attacks could not hit two at a time no cleaves unless they were 2nd level and attacking 2 zero levels for instance.)
A relatively normal roll 4 take the highest three
16 str ,11 int, 15 con, 14 dex, 13 wiz, 12 cha is a very average pc fighter who got +1 on hp and +1 on to hit (and +2 damage?) no garantee on bonus armor class or hp at all. -- I am operating on memories from back in the very early 80's.
And the above character could have still had 2 hp and die so easily.
Some people came up with even nicer than 4d6 take highest three.
For instance doing that plus re roll all ones started to become common.
Win the attribute or hitpoint dice lottos and you were a little more survivable... but the good news was most people threw away characters some if you didn't have 2 attributes 16 or better and i seen some just plain dice cheating. I saw DMs see one rolled on hit points and said.... nyeah reroll that please.
18 strength was common and 16 dex was common and 14/16 con was common but not necessarily because the game rules said they should be. House ruling to give everyone max level one starting hp became common too.
An AD&D fighter without winning the dice lotto or cheating at it took 2 hits to go down(or only 1). Thief, Magic User, Cleric went down to 1 hit which with poor armor class (for the non cleric) would likely be 1 attack.
Of course you had what? three choices in character creation so one dies boom make another.