The way I look at this type of situation is how much can I spend on model railways per month. I would love to walk into my local model shop and walk out with a Dapol B4, Dapol GWR Railcar, and a Hornby H class tank locos on OO gauge, but as I don't have a layout to run them on or the finances to do so, I won't be buying. I could get very political but I won't, suffice to say my modelling is down to my budget as well as my likes in the railway world.
Admittedly my modelling is strange as I model locations I have never been to, or have any connection with other than I like the look of them or what is available to the modeller, while I do use RTR stock, I like building plastic kits, which american and continental modelling give me, British outline doesn't at the moment. Kato's RhB stock is perfect, as it means I can save for it until it is released, and I don't have a myriad of classes and stock to drool over, this means nothing stays in it's box.