Let's find similar words which are being pronounced in a similar way:
see & sea /si:/
right & write /rait/
light & lite /lait/
miner & minor /mai.ner/
Good luck with this. The English language is full of homophones.
Just one thing - there is no such word as 'lite'. This is just a gimmicky alternative spelling of 'light', used by manufacturers and their marketing people.
This is kind of fun.
main - mane
lien - lean
vain - vein
foul - fowl
As you pointed out with poor vs pour, in some English accents a distinction is made. In others there is no difference in pronunciation. This can be seen when looking at the IPA spelling, which will vary depending on dialect.
I have to wonder if at some point there will be so much variation in English dialects that they will become almost unrecognizable, like has happened with Arabic.
Poor and pour are pronounced identically in most accents, as far as I know (usually like the word paw). However, I believe some people in the North of the UK would pronounce the "oo" like "moon".
I see difference between these two words:
Poor /pur/ , pour /pour/