Same reason why we have such advanced smart phones and laptops and yet still burn fossil fuels for our cars.
Maybe the Alien universe humans developed slightly differently, perhaps these things you're pointing out aren't that easy to make or the universe isn't compatible with such things (such as photon torpedos) because it's a more "hard sci fi" setting.
But humans do show a sense of progress, the Rage War novel has a humanity that is so advanced that it'd almost make Star Trek blush.
Here are some examples of their weaponry and other technology (contains some minor spoilers).
Nano-Rifles that shoot a swarm of programmable nanobots which can be ordered to either slice an opponent apart, or encase them and explode in microscopic explosions (billions of them at once.)
Laser pistol that can blow apart a Predator's hand in two shots. (And that's just a sidearm)
Plasma hand grenades.
Cloaking technology, one is invisibility while other one makes the ship look like an asteroid to an outside observer. (Predators still use better stealth because each time humans reverse engineer their stuff, Yautja innovate further within a week.)
Compact Rifle that can be programmed to shoot nano swarms, lasers and micro-dot bullets which also explode, and that's basically a "full stop sized" bullet, billions of them.
Shoulder drones that the marines have on each shoulder, can be deployed to survey an area and feed back to the marine tactically. It also fights back by firing lasers so it's a combat drone as well.
The Marine combat suit is skin tight, no more uncomfortable heavy armour for your infantry, you now wear a suit that functions similarly to the Crysis Nanosuit, it protects you from Xenomorph blood (a marine is shielded from an exploding Xeno, completely drenched in acid and on the molecular level, the suit shed parts of itself while neutralizing the acid to save the marine, this protection only works to an extent.)
The suit also has an inbuilt computer that reacts specifically to your thoughts, so no control panel really needed. It has various vision modes, injects you with drugs to certain areas in case of injury, it boosts your strength to insane levels (a marine ripped the remains of his own arm off with ease after an injury) and keeps you alive and prevents shock for a considerable amount of time so you can stay combat ready. Also slightly shields you from really deadly radiation and also it's a space suit too.
It deflects Predator plasma caster and other forms of ranged attack by despite being a skin tight soft suit, it physically hardens at affected areas.
Humans also use "Drop Holes", huge anti-matter fuelled space structures that literally bend time and space to make FTL travel a bit easier, this is incredibly difficult to build as one in fifty of these fails to work and one in three explodes once activated. However, when successful, it allows instant travel from one area to the next (but it's a one way travel, so you'd have to find another Drop Hole that goes back, and they can't be built next to eachother) - also, these Drop Holes are code protected, so only humans can use them.
Our fastest ships can go fifteen times the speed of light without the use of Drop Holes. The Human Sphere of Influence is huge, it'd take you 200 years on a fast ship to fully circumnavigate.
Our space ship combat is advanced, we use particle weapons, lasers, and combat drones to snip enemy ships with various weaponry and "micro nukes" which are superbly effective even against alien ships. Also, when a human ship gets damaged, the crew is immediately doused in a hardening gel that protects them from the vacuum while the ship's hull immediately closes itself and then the gel proceeds to melt away.
Also for the very fast ships, a simple cryo-pod won't protect you from such a velocity, so there's this special kind of pod that encases you in a protective gel to keep you physically shielded from the speed of travelling fifteen times faster than light. This gel once exposed to oxygen immediately evaporates.
Also, ship computers can now be spoken to anywhere, you don't need a specific console to speak to such as with "MOTHER", in the book, "FRODO" can be spoken to anywhere and has a nice personality as well. Also, you can turn on artificial gravity on or off at will.
So year, by 2692, humans are superbly advanced, having colonized and built cities on many worlds, building huge space habitats as cities on their own.
Also holographic technology is very advanced, there are huge holo-rooms that a guy walks into which is of a beach, he can literally feel the sand on his feet, that's how good it's become. Also there are a lot of holographic screens on ships as well as a couple of monitors.
Also, some alien ships are discovered by some humans that literally grow themselves, humans then incorporate such tech.
This is what I like about the franchise, it shows a huge sense of progress. Sure, some things seem a bit retro futuristic, but that can be chalked up to Weyland-Yutani being cheap (Nostromo) or humans going through some economically hard times. Remember in Resurrection there was a plague that apparently ravaged humanity.
And I think Winde is right, emergency equipment does need to be available and visible at all times especially on a ship.