No doubt, I could have built a decent Berg with what I've spent (and sometimes wish I had!) but with the Axial there's no massive outlay (Berg axles are expensive compared to an Axial) to start off and you can build the rig up a little at a time. As a first rig the Axial is ideal as it gives you 'instant playtime' as soon as you set it up, and also upgradability at a relatively low cost point, hence the 'bang for buck' argument. I really feel I can't justify selling my AX-10 and starting again, as I'm not really a crack driver so I'm never likely to get any advantage from a MOA.
You can really only bounce for a MOA rig of you've got a decent slab of starter cash to get axles, shocks, chassis, motors, wheels & tyres, electrics (which are more specialized) and all the other usual stuff you need to start out. Either that or you don't mind buying a bit of your rig every month and have the bits sat around for a while until you get it all together.