"Choice of packages, including DIP"
Very few when compared to all arm producers
How many ARM makers do multiple packages for
the same part ? Or evan make any low pin-count packages at all?
Not looked recently but I only recall seeing NXP doing any DIPs
"Same devtools for 8,16 and 32 bit parts"
You will need to pay for each one and is not the same, devtool only the IDE is the same all, compilers is a different product
My angle here was familiarity & re-learining new tools. Unless you're doing high volumes, using a familiar devtool can easily work out cheaper overall than using a cheaper part that means you need to learn a new toolchain.
The IDE, programmers and debuggers are the same. The compilers are similar enough that you can switch easily.
Purchase cost is a non-issue when doing commercial work, and the free versions of the 16 and 32 bit compilers are entirely useable for a large proportion of applications.
"Manufacturer with a long track record of good availability and not obsoleting parts"
Only ONE manufactures, arm space have dozen with a muck long track record
Which ones exactly ? NXP have been bought so uncertain, and they had a track record of up-reving chips and obsoleting the old ones, Atmel have a poor track record of obsoleting, and have been bought. Several other players haven't been around long enough to establish a track record.
"Availability of low-cost programming/marking service from manufacturer"
For sure microchip dev tool isn't low cost, maybe low quality but not low cost, arm programming tool is cheaper and better, in fact you can program arm with more than 10 different programmers from different vendors
What does that have to do with my point about being able to order pre-programmed parts?
As regards programmers, there are plenty of third-party PIC programmers, probably at least as many as ARM. And they fully document their ISP protocol. (Have ARM SWD docs ever been formally released by any manufacturer?)
And Microchip is one of the few makers that produce programmers, which means you're guaranteed that new parts will be supported as soon as they come out, which is rarely the case for third-party programmers.