I've noticed this too over the past few years!
Music Stars are really high in demand, especially recently, and that really sucks you can't find one! ;A; Your feelings of frustration are totally valid, and the fact that you've been waiting for one since you were a kid?! That's a terrible position to be in! Tamagotchis have become collectibles, unfortunate at is is, appealing to former 'gotchi owners and shell hoarders alike. There's so many people like you in the same position - I've been searching for a V5.5 myself over the past year! And they're very hard to find, along with a good price. Most listings I've mistaken for one are just the original V5 too! so many heartbreaking visits to Tamashell.com have ensued XD
Trust me, there's many people all around the world who have a Music Star in storage and don't even know how valuable it is. You
will get your hands on one someday, mark my words - my first Tamagotchi back when I restarted my collection was the Glam Rock V6, listed under 'tamagotchi' with nothing hinting towards the type of tama it was! And I didn't even know there were different Tamagotchi versions at the time! You have to be patient, no matter how painful the wait is. I have a search under "tamagotchi" listed on my favourites bar that I check every morning, set to newly listed + used condition as new in package listings are usually the newer models or unfairly-priced new-old stock. The less specific you are with your hunting, the more rarities you may be able to find.
You might already do this though, haha! I'm just rambling now, good luck finding your dream Tamagotchi! We're all rooting for you! ^^