Normally in conversation, I use the subjunctive in these situations naturally:
“I’ll just do it so that he not have to.”
“As long as he understand what I’m saying, it’s fine.”

If that is true, then your use of the English language is certainly not “fancy”, but rather it is ridiculous. Most people who wish to learn more about English grammar are people who aim to speak the language more fluently. Thus your obstinate approach seems quite counter intuitive.

Rather than insisting on using such nonsense as, “If anyone WANT to climbe that mountain,” perhaps you’d do better to improve your grammar:

I’m showing an historical viewpoint on the subjunctive and it is heard and seen every now and then.

(And no, I’m not referring to your questionable use of “an”)

In general, I found that all other commentators had sensible thoughts on the subject. Well, except Kate of course, who appears to have taken some sort of psychotropic. Thanks everyone for the valued information.

Dear God, I want you to make real wishes real wishing starlight starbright real wishing wishker lobster real wishing star fairy real wishes come to life as long! I wish Jeff Becky Kelsey Loverude whole people from Massachusetts police security Danielle work study school nipmuc Danielle work study students teachers Aunt Julie Olsen and her family Uncle Tec Aunt Rhonda Grandma Jan Erikson and her friends Bakken family Grandma Jan Person Brittany Bakken and her husband Ashely Uncle Dave and their family Uncle Mike Cal and their family will all be Gone gone forever tomorrow, No turning back! Amen

“I’ll just do it so that he not have to.”
“As long as he understand what I’m saying, it’s fine.”

I would never say “he doesn’t have” nor would I say “he understands” there above. I would normally say, “if she should climb” though. It’s all about how one was raised and how he learned and picked up parts of his language. I’ve always said it that way and have never been told I was incorrect. I’ve been told it sounds old-fashioned. Be that as it may, it’s still the subjunctive. Again, I shall close this case again. Peace be to all and Merry Christmas.