Storm Kings Thunder (and probably other 5e adventures) suffers from the same problem - a large set of seemingly random "quests" that the adventure wants you to hand out as soon as you talk to a certain person. I'm not sure exactly, but I think 4e started using this in adventures, and it seems Chris Perkins still favours it (at least in the adventures he's published recently, although he doesn't seem to DM that way). Personally it's a design style that I really hate, as a DM as well as when I am a player - I think it's terribly lazy design and a terribly bad example for DM's on how to run a good sandbox.
Certainly "back in the day" (1e), published adventures were basically the dungeon, maybe a paragraph of background up-front, but usually the assumption was that the PC's wanted to have an adventure and so there it was. Some might have had the old "rumours table", usually rolled on randomly when PC's talked to people, but those were not quests per-se, they were more like potential plot-hooks / useful information (including false ones). For example I'm currently running B5 (Horror on the Hill, 1983) - there are no quests, not even much of a reason for the PC's to go and go on the adventure - they start in a bar, talk to one or more people, and hear some rumour(s) about a ruin on the nearby hill and what might be there. Then they go and have their adventure, killing monsters and taking their stuff (or the DM pulls out a new adventure module lol). Of course, the way I'm running it, the entire start is different - I actually started with the Nightstone section of Storm King's Thunder, which lead to the PC's heading into the forest to try and find all the villagers who were captured by Hobgoblins etc; various PC's also have backgrounds tied to key villagers. So far, no real "quests" have been handed out - the PC's have sufficient motivation based on their backgrounds, and what's going on, to create an adventure. If and when I do incorporate any of the written "quests", they will be ones that make sense and naturally come up in play with known NPC's, not any of the random "go hundreds of miles to village X, and tell person Y their neice is dead" types of quests that are in Storm King's Thunder...
As noted above, the key to making this work is to make it feel "real", i.e. logical, not simply "go here, talk to bob, get a quest". Especially when a lot of the quests are really side-treks - those ones I try to minimise / delete. Definitely think about how to work what's presented as a quest, into something that ties into the back-story and/or current / future plot points of your PCs. Think of these 'quests' as ideas, for you as DM, to consider on how you *might* include them in some way. Wherever possible, allow the players to stumble into 'quests' naturally, through their own explorations, following whatever takes their interest - only force rumours / quests etc onto them if they appear lost for ideas / direction.