Must just be you
I've returned at least three personally. One in the car park behind my house, several left behind at a karate club, I returned a credit card that was left in a card reader in a store I worked in once (and nobody else saw it and it was only discovered after-hours - it went straight into the work safe when I found it and the bank notified next morning).
My wife's returned several more, including one with several thousand pounds in cash - turned out to belong to a penniless student who'd been loaned the money by her parents and was taking it to a debt collection agency to clear her debts in order to stop her possessions being repossessed. Cash was the only thing they'd accept, and if she didn't pay she'd have lost everything - as it was she was already owing her parents thousands - can you imagine what would happen if she hadn't had that handed back to her? You have *never* seen a more grateful person in your life. If you could sleep well at night knowing that you'd just taken that money, I don't think I'd want to know you.
Also, my wife used to be very clumsy before I met her and she lost her purse several times - every time it was returned with all the cash / cards intact. So we're not the only ones out there.
A theft is a theft. Technically picking up 10p from the street without handing it over to the cops and waiting for a 6-month "ownership claim" period is theft. However, if no-one claims it, it's legally yours after that time and the police will return it to you - no matter how much money it is.
Theft is the taking of property not belonging to you with an intention to permanently deprive. I think that applies here to someone that SOLD the device on to a tech website who then opened the thing up after they *made* the company that owned it disable it via a remote security protocol. Legally, you deprived them when you sold it (and that's handling stolen goods in itself, not to mention a list of other crimes), and the "fence" at Gizmodo then categorically destroyed the device. That's criminal damage, for a start, and intention to permanently deprive. Reading this story, you can tell just from the attitude and the things cited that both "handlers" were idiots and deserve to be arrested, if not charged.
Now, the 10p thing is different because it's almost untraceable but I'd let you off with interpreting the law loosely in that case... but a wallet will contain identification, obviously "belongs" to someone, who WILL be looking for it and who will almost certainly try to reclaim it from the police, local shop, security, whatever. You've gotta be a scumbag to do more than look inside it in the hopes of being able to contact the owner. Same with the phone. It belonged to someone - whether that's a company, individual (how do you know the original Apple guy didn't buy that phone on some special internal Apple sale with his hard-earned money, and thus was HIS property?), or whatever, it wasn't theirs to mess with. They crossed the line the second they thought about selling / buying it.
And I hope you never lose your wallet at a critical point in your life - and I only hope that because I'm actually a nice person - I think it would be all too easy to laugh at you if you did.