I have to disagree that shoes that last forever cannot be comfortable. They do take some break-in time. Last forever implies that the boot can be re-soled. Not many shoe shops around nowadays that do that. Plus you have to really take care of leather if you want it to last long. If you let it dry out in storage, they will no longer be comfortable. My old heavy mountaineering boots were comfortable as long as I cared for them properly. Another factor is your body weight and foot size. I find that heavier boots are proportioned for the heavier person with larger feet. You cannot just scale down a heavy leather boot and expect it to have the same qualities unless you also scale down the thickness of leather, flexibilty of the shank, etc. In general big people like boots; small people do not.

All that aside, the main issue with boots vs trail runners is weight, fit and economics. And do not just look at trail runners- low cut light hiking shoes also are light. There are more options in lighter shoes so you are likely to get a better fit if you have an odd foot. A good boot will cost 2-3 time more than a trail runner so if a trail runner lasts 2-3 time less, the economics is the same. Also, light hikers and trail runners go on sale regulary - no reason you cannot find half-price sales. I use Merell light hikers and they only last about one year, but I can regulary replace them for about $60 on sale. They fit my feet, and that is mainly what I am concered with.

Other reasons you may want boots - 1) difficult off-trail travel, particulary bushwhaking and sharp rock, 2) lots of very wet trails- you can actually walk through a short ford and not get wet, 3) need the shoe to accomodate a crampon.

My impression (may be outdated) was that Danners fit more people poorly. Soloman's run wider. The old saying was that Danners last forever because you rarely wear them. But if you have that foot that fits Danners, than OK.

You may want to gradually get used to hiking more in low light hikers or trail runners. If you use thicker wool socks and size, add a Superfeet insole, size it up to fit and add gaiters, you may find the trail runners just as suitable as boots.