What you are describing is a function of the evolution of D&D over the years. In old editions, the Thief class (later Rogue) was pretty much a necessity as the only person who had the special power to deal with traps. As D&D has drifted further and further away from its dungeon delving roots and more into player freedom, it eventually allowed for cross-classing skills (picking a skill your class can't handle, but requiring double investment), and later making many skills class agnostic.
This affected the Thief class (Rogue) more than any other, but it isn't a bad thing.
A common theme of modern pen and paper games like 5th edition is to say "No class is required. You could make a party with no rogues, or no clerics, or no fighters, and still manage just fine." This is kind of true. Individual classes are less and less necessary, but character roles remain very important. You need party members that can inflict damage reliably, heal wounded characters, talk your way out of trouble, take the lead in exploring dangerous places, and so on. All characters have the potential to take traditional Thief skills, but keep in mind that they're trading off other skills that may be typical for their archetype.
Also worth noting is that 5th edition handles the hard identifier of "traps" more differently, and frankly, better, than any other previous edition. There is no catch-all trap handling skill, not even a catch-all trap spotting skill. Traps can be identified and disarmed with pretty much every skill in the game, depending on the trap. This goes around to defining trap as an obstacle that is dangerous to the players if stumbled into. A loose log on a hill above you may require a nature check to spot, and it may require a survival check to bypass safely. A series of indecipherable arcane runes may require an arcane check to decipher as exploding if crossed, and disarming it may be impossible, just a matter of not crossing them. And of course, locating a pit trap may require a Perception check to identify, and may require a Thieves Tool check to jam the trap door shut. In pen and paper at least, the way to disarm some traps tends to be less straight forward the more simplistic they are, allowing for more improv, while the complex traps are usually tied to a particular trapping.
All that being said and getting to the point about rogues... Do you need one to deal with traps? No. Are they still the best ones at it? Generally, yes, but not exclusively. This is exactly the same for all other classes and their traditional roles. Wizards remain the best at blasting and controlling enemies, but hold no exclusive dominion here. The cleric is still best at healing characters and curing debilitating debuffs, but so too can other classes do this, just not quite as efficiently, and a simple look at their spell list reinforces this fact.
So what are rogues good at? They're valuable in whatever you design them to do. You can focus them as troubleshooting dungeon delvers by taking skills that lend toward locating and disabling as many kinds of traps as you can come up with, but this is player decision. In the defined character class abilities, rogues are great as tanks in MMO terms. Sound weird? It is. Rogues wouldn't fight the way a traditional tank fights. They're skirmishers. They dart in and out of melee by disengaging and making it difficult for enemies to pin down vulnerable party members. More directly, rogues have abilities that literally soak damage. They aren't the same caliber of tank as a barbarian in 5th edition, but they fill the gap somewhere between barbarian and paladin, being a mix of durable and having pretty large damage output potential.
TL;DR? Rogues are able to mitigate a lot of damage through a mix of skirmishing tactics and special abilities that soak damage. Rogues are also in the middle ranks of the consistent high tier damage dealers. They shouldn't be viewed as a character class necessary for exploration anymore, but instead as a fighter-type class who specializes in indirect fighting. They retain some advantages for exploration over other classes, but are not longer the only class able to do so.
