"With that said, are we to assume that because of the lack of those type of connectors coming out of the factories, that this indicates the manufacturer's lack of understanding?"
That would be a logical assumption. Either that or it's cheaper to build.
Elaborating a little, I generally use an external mixer, Mackie 1202 or Behringer, and run my mic(s) into that. I then use a Send to route the mics back to the keyboard.
This way I can use the keyboard effects and harmonizer on more than one mic, in case of a guest singer. Also, it allows me to use phantom power mics when I want to.
However, on the small jobs such as nursing homes, I often want to take as little gear as possible. In these instances I run the mic directly into the keyboard, and the keyboard out to a small p.a. or powered speakers.
I find the mic sound and the harmonizer in the PSR2000 more than adequate for most jobs. It is crisp and clear with virtually no noise, when adjusted correctly. If you use the harmonizer properly it works fine for my applications.
I sometimes use the compressor/limiter on my mic, and I find the onboard effects and seperate mic e.q. easy to access and use.
The XLR input is not a life-or-death point, it would just seem perfectly logical to have one.
DonM