And yet the classic hits format is among the most popular, most listened to formats of all radio. So my sense is the complaints you're hearing are coming from people who don't listen to the radio anymore. If they don't listen anymore, the stations aren't programming to them anymore.
By definition, a format is based on repetition. That's what makes it a format. So there is a pattern of songs that get played so many times a day, so many times a week, and that's the format. If they seem repetitive, it's because they are. Radio is not going to change how it works for the 1 or 2 % who find it too repetitive. The people who complain are the ones who don't listen, because they've already made their choice. There is no programmed radio service that isn't repetitive, unless the user creates the playlist. So if you're listening to Sirius, or any other automated music distribution service, it will follow a pattern, and it will be repetitive.
The format is also based around a consistent sound. That means you will typically hear one kind of music as part of that format. So if you want variety, it requires the user to change the station to find that variety. The days of one station playing everything ended in the 1970s when format radio began. Even AOR rock radio narrowed its focus by the end of the 1970s so that you didn't hear random album cuts, but specific focus cuts that were usually decided by the record labels.
Were there stations playing odd album cuts back then? Sure. Were they popular? No. They might be college stations or small market stations. But the big stations that got ratings were the ones that focused their music on a sound and a group of songs.