My inlaws have never once done anything for my kids bday, Christmas etc. I do not think it is a reflection of how they feel about them (mother in law passed 15 years ago). Quite to the contrary. They were/are crazy about my kids.
I equate this somewhat with valentines. It is NOT important to me that my husband makes a big deal about it. What IS important is how he treats me consistently.
My daughter was floored when my parents bought her a new iPhone for graduation. Her response was, wait, you're giving me a gift because I am graduating? I didn't know I would get gifts for graduation. She was so grateful but didn't expect anything and was very blown away by the outpouring of gifts and sentiments people gave. My mom was brought to tears because she was so unassuming.
So much of our disappointment is because we have a preset expectation of others and when they don't live up to it we are hurt.
Keeping score is a miserable way to live. You husband remembers his parents because he wants to. It should not be done with an expectation of receiving the same.
And just so you know, her grandfather that has never bought her a single thing in 18 years is one of her favorite people. And he loves her dearly. I would've never dreamed of mentioning one thing to him (or my mother by love) about it.
My parents remember every bday, special occasion and make their own special occasions with my kids. They are active in their lives. It's very much my mom's personality to be generous to everyone not just her family. It's part of her DNA.
Difference in how people are. Not a reflection of whether they are loved. Just my thoughts.
Also, we make our kid's day special. If someone adds to it, wonderful. Whether that's a card, phone call, email or whatever.