Keep trying newer bikes and you will keep spending money. Money you could spend on other things like bike trips. Most so called improvements are part of the sales & marketing thing. As long as your bike is well serviced and set up you should get all the pleasure you need out of it. Don't be seduced by the I've got better, wheels, frames, gears fanatics you meet on bike forums unless you want to. I have old [1980s with steel frames. bike weight 20lbish]and new bikes. the big improvements for me are being able to change gear without having to move my hands from the bars. Thats it.