It's not because you're lazy. It's because you don't know how to play very well or very much which limits how much you practice. If you knew more repertoire or had the ability to play them, you'd spend more time on them. It's not the hours. It's the interest.
Interest doesn't happen automatically. It requires background knowledge and experience. The more of it you have, the more interest you'll have.
Even, i told everybody is great in this forum, i dont like very much this answer. Why? You explained all well, but must to dissapoint you. It was just laziness. I have had job, boyfriend, many things, so i didnt have energy also for playing piano for hours. But now, i have more free time, so i can. Today i played 2 hours.
So, only needs energy to invest time in playing. Regarding my knowledge, i can tell i know a lot ( for person which doesnt have musical education). I am playing already 20 years ( i am not professional, but i am very good amateur). Also i am recording my playing and when i play bad, i can correct all mistakes and errors or performance and musical ability.
So, its not that easy, that i dont know much so i dont have interest, because you dont know how long i am playing or anything about me.. And i am telling you in this way, because this doesnt have any sense, because you dont either know my repertoire or anything about me, so i really dont know if you have some Glass ball to predict all?
Regarding my repertoire, I have too many Pieces on my repertoire in fact and play many many things. So, how can you assume that i dont know anything and play very little pieces in repertoire i cant imagine really. Because i dont know if i told that anywhere..
I only so far told that i am having problems to look at the piano when i play fast and that was all about me.Yes. and told that i am momentarily playing only 1 hour a day and that i am not satisfy because 3 years ago i could play even 6 hours per day. So i think that lack of my musical knowledge doesnt have something with interest.. I have big interest, but I have the other things to do too, so often i am not in the mood to invest energy and effort in every piece. I am playing Sonata Apassionata and many many things momentarily. ( did you finish college of Music or what level you are?)