Are there any complete Bitcoin systems? It seems to me that to keep Bitcoin both decentralized and secure, the whole of the Bitcoin process should ultimately depend on each user, or rather, that the involvement of each user should incorporate all aspects i.e. mining, full nodes, wallets, and exchanging.  Perhaps this is too much to think about at this stage, or maybe I simply have not found this, but is there any product or community that is focused on empowering individuals with simple systems that incorporate ALL of these aspects, and may I dare say, while being itself decentralized?
No, not to my knowledge. Also, it doesn’t make sense to me to want to incorporate all these different aspects into one device.

Mining devices need to run continuously and produce a lot of noise and heat. They also need to be replaced eventually, as they get obsoleted by better technology. As such, they are most cost efficient if they just focus on the mining algorithm.

While full nodes also run continuously, they can run on fairly small machines more suited to quieter environments. They run more complicated software than the miners and need to have software updates frequently, while the hardware can last.

You don’t want wallets that store large amounts to run all the time, as that increases the exposure to potential theft. Wallets for daily spending tend to be thin wallets which will catch up with the network quickly whenever you need them to, which also is beneficial for running them on small devices that you can carry around.

Decentralized exchanges are even harder. In a way, these are covered by mobile wallets in that they allow users to meet up and trade directly. The challenge with decentralized exchange systems is the interfacing with fiat currencies. I don’t think there is a widely popular solution yet, and it doesn’t appear likely that a majority should be running any such solution.