people only started using the new pronunciation in the last 10-15.

As someone else pointed out already, this is untrue. While it may not have been popular in your circles, it definitely was in others. I've been saying it with a hard g as long as you have with a soft and I'm not the originator either.

English linguistics doesn't indicate anything at all.

They absolutely do. That's why you can sound out a word you've never seen before. You may not always be right when you do because they indicate, they don't define.

There are no rules about word construction or pronunciation.

There are, there are just exceptions. For example, an e at the end of the word is silent. I'm certain you can give me a word where it's not, but there are at least six in this paragraph alone where it is.

if you are understood then you have pronounced them correctly

In this logic if someone has been pronouncing a word all their life with a single pronunciation and travels to another location with a much different accent they can only now be pronouncing the word wrong.

If understanding is also the only metric then a hard g would still be preferable. Not only does a written g tend to make people lean to a hard g in my experience, but there's more words that could be mistaken for a soft g pronunciation.

You could argue that the original pronunciation is archaic,

Could I not argue that the original pronunciation has fallen out of favor?

the word itself is like 35 years old

Is there a time requirement for pronunciations to become archaic?

since there was only one acceptable pronunciation

Which isn't a time that existed, as we've established

who aren't likely to change.

Given your stance on language this is absolutely a you problem. If the rest of us collectively decided to understand it as only with a hard g, you would not be understood and therefore be pronouncing it wrong by your own logic.