Thank you for reminding me of this channel, I'd forgotten about it.

Interesting about the merging. Schwa has always been weird for me because in my dialect it can be many sounds. I grew up saying "obstruction" as [ʌbstɹʌkʃɪn] like those around me. Then I hit grade school and was told by a straight-faced teacher that both the first and last syllables in this and similar words were schwas while pronouncing them differently :)