Non-destructive editing has been on the list of GIMP feature requests and roadmaps for many years. I may be wrong, but it sounds like the problem is more a misalignment of project goals with target user requirements rather than a sheer lack of development resources at this point (since so many other features have been implemented in the meantime).

I could be wrong too however we are both just stating opinions and mine is proven to work eventually so why am I being downvoted?

Because "code it if you know how or pay someone to code it" is not an answer when talking about software and lack of features, even if it's OSS.

OSS software is built by its community of developers, not by its community of users (even if those overlap a little, the second is many orders of magnitude bigger). So when someone criticizes it that it lacks feature X, telling them to "code it" themselves is not really helpful. They already know they have this option. If they had the knowledge, inclination, interest and time, they would have done it already. Not to mention that even if they tried, community politics and roadmaps might be against their wanted feature.

Can we accept that someone is free to criticize a piece of OSS software without being obliged to fix it himself?

But these kind of critics about known problems don't add any value.

Or, in the real world, where people just need to get shit done and do not know how to program, I'll just buy photoshop. Why in the world would I spend more, in time or dollars, to add a feature to Gimp which already exists in Photoshop?

Did you read my suggestion as dictation? It was just a suggestion, nothing more, if you prefer PS, go for it, no worries.

I am saying that yours is a poor and unrealistic suggestion.