Was the buggy, slow Parrot VM "state of the art?"

Nope; it was basically a rewrite of the Perl 5.6 VM with more sanity.

Was its pathetic JIT compiler (to which I contributed) even vaguely informed by IBM's Jikes RVM or Sun's Java VM?

Somewhat, but those approaches are still wrong for the types of languages intended to run on Parrot. Better examples are Slang and Dis.

Did the implementors consider Greg Wilson's surveys of garbage collection techniques?

Yes, in fact.

The biggest problems with Parrot were:

• Its first several years dug a huge hole of technical debt in the form of poorly written code written to do the wrong things while exposing far too much of the internals under the guise of an API. (When normal control flow is a mixture of C calling conventions and Parrot calling conventions and HLL calling conventions, you have a mess, and nothing will run quickly.)
• It's no fun to fix that and no one wants to do that.
• Even if you find people who want to fix that, it takes forever to fix that when you have to support great wads of buggy, awful C code written as proofs of concept and somehow covered under a poorly conceived deprecation policy, which happens to be self-reinforcing behavior, because if you can't fix things fast enough to support downstream users, they'll write even more buggy and awful C code to poke in the internals, and you have to support that too.