If your boss just piles more work and doesn’t acknowledge the work you have done, that’s crap. And yes it would feel shit. But your effort is directly impacting them. Any decent boss would appreciate hard working staff because it directly impacts them.
But the equivalent for a sahm would be a child or partner not appreciating them. Not the general public. If your boss doesn’t appreciate the (as an example) 20 hours you out into a report, someone outside work showing you appreciation for your hard work would be strange. If my other half told me he was proud and appreciated the work I put in to my revenue report, I would laugh.
If your partner, who isn’t your boss but the nearest equivalent in a sahm situation, doesn’t appreciate you and just piles more stuff on you (who else could be not appreciating you and piling more work on you?) all the validation outside the home isn’t going to make you feel better.
If you open a door for someone you have done something that directly has impacted them, even in a small way. Someone being a sahm has no direct impact on anyone else. Just like being a working mum has no direct impact on anyone else.
of course people get frustrated if they have cooked a meal and the people you cooked for would prefer a take away. Again, you have gone to effort of doing something directly for that person. Who is going to say ‘I appreciate you cooking a meal for your child even if your child doesn’t want it’? Surely it would only be your partner or your kids. But thats something you would be teaching your child and they will grasp as they get older. The outside world can’t fill the void of kids not appreciating your effort.
Besides which do you think that doesn’t happen to working parents? Do you show your appreciation to working parents who also cook meals for their children?