Which makes the 5e orc twice as powerful compared to a level 1 5e PC than a 1e orc is to a 1e PC. As I said, apples to oranges.
There was no CR in 1e. You could totally face orcs (or heck, gnolls, zombies, an ogre, etc) at 1st level. ('Face' not necessarily to be taken literally.) Part of the appeal, I should think. (Of course, CR /guidelines/ don't prevent you from facing an Ogre - or disinterested dragon - at first level, they just wave a red flag at the idea.)
So it's an Orcs to Orcs comparison. Orcs just have bigger hp/damage numbers in 5e, like most every monster, just like 5e PCs have more healing to patch themselves up after fighting 'em.
But, hey, whatever, Kobolds (CR 1/8 lowly enough for you?):
1e: 1/2 HD, 1-4 hps, AC 7, hit the frontliner on 18 for 1-4(2.5) damage (0.375 DPR, no crits, officially)
5e: 5hps, AC 12 (yeesh), +4 to hit, so tag the frontliner on a 14, for 4(1d4+2) damage (1.4 DPR, 1.6 including crits).
But what's the point. You're arguing that AD&D rest and recovery is comparable to 5e's, and that's just laughable.
I get that it /seems/ that way, when you look at overnight recovery vs 1hp/day + CON mod/week or whatever you used back in the day. But that's not a meaningful comparison, because the latter just didn't happen if you had any renewable daily healing resources. Instead, you healed using those. The difference on that end is thus largely bookkeeping. In 5e, you just recharge everything in 32-48 hrs (depending on exactly how you rule the 24 hr hard limit, getting back all your HD adds at least 24 hrs). A low level party in 1e could go through a number of re-memorization cycles in that time, and also be at full hps with all their spells ready. It's just not a major difference in the way the system dictates pacing to the campaign.
And, the 'solution,' if you do want to go even slower - as if you were running an apocryphal/non-viable healing-less party that needed a week+ of rest - is not to re-write tons of rules, it's a simple variant that changes the length of short & long rests.