I suppose it vary significantly, and may be me justifying liking new things, but here goes:
Your longer term big ticket items suggested are not necessarily more valuable than smaller items (though I don't know how "small" a car really is in comparison).
My thought process is as follows - There is significant uncertainty in whether a house or given college degree or early retirement is going to be worth the time or money, especially years on.
Houses just crashed a few years ago, and for lots of people it was a losing proposition. College degree costs vs jobs and actual increased income seem to be on a similar bubble path right now. Early retirement may not be desirable due to enjoying your job...
Your "trinket" items are also perhaps subject to significant potential disputes as to the worth of them. If all you want is a cell phone, any $30 e-bay flip phone is fine. But I would argue there is a significant value to be had in having a smartphone. It's not worth it for everyone, but a smartphone can do tasks the flip phone just can't. Newer smartphones don't get as big a bump, but there are apps that each successive phone can run that some older class of phones just can't. Go back 4 years on Android, and you might have gotten a 2.2 OS. There are many apps that are 2.3+ with functions in them that are 4+. This may be of no value to you, but I would argue there is a non "trinket" value to be had here.
The latest Big Screen TV may (and there are variables) use less energy due to being LED backlit vs Plasma or LCD. It might have a better integrated set of tools like Netflix and Amazon. It might play 4K media instead of 1080p or 720p. These are actual upgrades, though again, it superficially may look like it's doing the same thing. At the most superficial level a we all should still have CRTs. That's a potentially valid position, but I don't think we can say having a newer TV is a waste of money.
The latest model car is potentially the weakest "toy". I have a 2012 Legacy and am seriously thinking of upgrading to a 2015. Why? 1) CVT so better MPG by ~3MPG. 2) crash avoidance system. 3) Adaptive cruise control. 4) Built in back up camera. 5) Cross traffic sensors.
Now, this is a special bunch of upgrades in a particular model, and not there for every new model year. But each year, some car is coming out with non-trivial improvements to safety, fuel economy, and features. Buying new cars isn't an investment - you'll get no argument from me that it's a money loosing proposition. But no more so than buying vegetables at a grocery store and making a stir fry at home vs a value menu meal from McDonalds. That is to say, newer devices can have real benefits.
Now I agree if we're talking fashion, jewelry, the latest Madden release(but only for one year back, then there's the value of still having multiplayer over the net)...
I also think about inflation. Many smaller gadgets will last and function for years, they don't lose their value as fast as the cost goes up. Most consumer electronics don't follow this pattern, but many appliances seem to (Kitchen appliances such as Bosch Mixers etc), as do tools etc.
For many new "toys" it's buy it now and have it, or hope I can buy it later... Things I own would only go away if something catastrophic happened, and I'd still have lost the money I could have had instead - and money that's likely loosing purchasing power the longer I hold it.
Anyway I've rambled on, it's late, and we might actually agree.