The disadvantage of many small pipes is that if they are too small, they may not be useful for some purposes, and if you make them too large, you could end up with lots of wasted space when some cables don't need that much room, and you will generally run out of available conduits to put new cables into sooner than if all of the cables had just been in a single much larger pipe. If you make them different sizes, then you create the risk running out of a pipe size if one size is used too often.
If the ratio of the cross sectional area of the available room in the common pipe to the cross sectional area of the cable you intend to run through it is high enough, damage to the cabling you want to run through or any adjacent wires is actually very unlikely to be a concern. Companies could easily add a more protective layering on their cables that would add to its size no more than a customized conduit would to further protect them... which is still going to be cheaper than digging a hole just to run some new conduit.
Actually, some of those could actually be pretty useful. An option to close tabs unvisited in the past x minutes would be particularly nice to have (where x is a user-configured value).
I suspect, however, that this kind of functionality can be added via plugin extensions to the browser, and may not need to be in the browser code.
That's only trouble-free for people for whom the price of Intel compared to AMD is already not a concern.
So in other words, what you really mean is that what works best for a trouble-free life is to just be rich enough that you can buy your way past any problems.
And who can argue with that?
"Catch a wave and you're sitting on top of the world." - The Beach Boys