I don't know why it's limited to 1.5 GB?

I know Amiga OS4.1 can use up to 2GB, but as they're both 32bit OS, shouldn't MorphOS see up to 4GB, including graphics cards etc.

Any chance I'll be able to use the full 2GB on my Powermac in the future?

(note, I've never run out of memory even with only 1GB, so it's a fairly accademic question.)