I wish, and this is not a slight on you, Alex, that the world went back to producing items that were serviceable and repairable rather than disposable.
I'm with you. Totally apart from whatever the time/cost/environmental tradeoffs are, it somehow feels wrong to toss something whose failure has a really minor root cause, simply because the design doesn't provide for easy mitigation of that minor root cause. While I think the pro's and con's pretty much wash to a matter of personal preference in the case of shoelaces, the same can't be said for a $200 flat-screen TV with a blown audio output chip. In the latter case, unless you're in the <50% of electronics engineers who'd go for it, there's not a cost/energy effective option for getting the thing fixed vs. just replaced. Or worse still, a bunch of annoying bad+bright pixels.
I'm pretty confident that you get this, but since FrayedGate has been called, I might as well be thorough...
Laces are not probably not a big environmental impact, but, a special trip to the store has an impact ... If I can repair them now I can use them now (or tomorrow)...
All kidding aside, it is a hell of a lot quicker to fix at my house and many of these solutions can travel with me for an on site...
Fraying likely has been a slow process that a hiker has been noticing for a while and can probably put up with for a while longer. The obvious approach to making good use of the store is simply to live with the frays and/or temporary at-the-house-or-on-site expedient until there's a bigger reason to get near to inside the store (well, or your chair to use REI.com or Amazon). "Shoelaces" just needs to get added to the shopping list. Net added time: next to zero. Although, as far as being quick goes, sadly we've already blown it just in the process of starting and then attending to this VFTT thread, me especially. :-(
And who's to say the new laces don't fray on the next trip out?
You just have to tie your laces such that the ends and loops don't hang down below the top of your uppers. You can do this either by using shorter laces, or by using a 3-stage tie in rather than the standard 2 stages.
Most of the trails I hike don't have an EMS mobile kiosk that follows me around while I hike.
Next best thing: perhaps your hiking companions are following this thread, and will bring along a set of laces to surprise you with when you turn around.
Lastly, don't get me wrong. Although I think I'm calling it right when it comes to shoelaces, anyone taking a look at the extra stitching and seam seal on my Osprey packs will be quick to understand that I'm much more a fixer than a replacer. It's been a long and hard process to learn where to draw the line and realize that however elegant it may to spend a crazy amount of time fixing some inexpensive thing simply because I can, it's a real waste of scarce time vs. the alternative uses for that time. Buying new shoelaces goes against my grain too, but I've concluded that it really is one of life's true no-brainers.
The 'good' news: it doesn't come up that often because these days: my laces and associated aglets are fairly consistently outlasting the shoes they're threaded onto.
Alex