PHP has pretty good dB abstraction if you use Doctrine, Cake or CodeIgnitor.
I'd rather not be pulled into a whole framework for something that's relatively simply. PDO is the generic solution for that use-case, but it's still a bigger hassle to use because it follows the same inconsistent error signalling model of PHP in general amongst other things. SQLAlchemy is what PDO should be despite the fact PDO has had 2 extra years of development.
There are some other, less encumbered ORM/DB solutions out there for PHP but really they are at best maybe approaching SQLAlchemy feature-wise and in ease of use.
Magento? What if I don't want, or can't use Apache/MySQL? PHP has always been uncomfortably close to those two.
More spooky to me, though, is that somehow they've managed to include 4 distinct, extremely critical security faults that were just due to outright negligence on the part of the the devs to not check their inputs or do code-reviews in the last year.
I'd strongly avoid ever writing any custom eccomerce system unless you have a large team or it works directly from an ERP.
But sometimes you have to. Some clients have particular needs that cannot really justify a drop-in solution. Those that can support such a solution don't tend to need all that much in the way of back-end development.
As for wordpress, and phpbb.. Your perfectly right. I think your php knowledge may be slightly dated.
They're what people are actually using PHP for in the real world; that and other old solutions. The majority of companies/people I've seen willing to try any of the newer, better done PHP solutions like Laravel just choose to go with Python or Ruby instead.
They're also both actively developed and example of successful PHP codebases in terms of number of users. WordPress in particular is so successful there are plenty of 'PHP' devs that only really do WordPress.
My point with bringing up WordPress, though, was that you said PHP is somehow better for blogging which I find strange given a simple blog only needs a decent ORM to become a trivial exercise, and your biggest options for a CMS/Blog combo on PHP are abysmal codebases you'd never want to touch personally.