I tried building a variety of different manufacturer's cars over the years and i've also pretty much lazily settled down on Tamiya bikes and cars now, but mostly because they seem to release racing cars and bikes that i'm personally interested in. However, the direction that they are heading, and the competition from other manufacturers might steer me back to the other companies.
Over the past couple of decades, Tamiya's quality has made them the king of plastic models, but in recent years has faced increasing competition from some other Japanese and Chinese model companies. Fujimi and Hasegawa has come out with nice street imports and rally cars to make you seriously consider how you should spend your precious hobby dollars.
I'm sure that modelers are definitely more interested in building a Tamiya engined model over curbside, but then those kits will certainly cost more, perhaps more than what their customers are willing to spend. The direction that Tamiya is going is certainly making me feel more worried too. The tooling of new kits are featuring diecast chassis, mostly to prepare a masterwork completed model for customers to buy right away. Sure the assembly seems easier, but I feel i'm sacrificing some of the detail that I want to have. Their marketing of increased realism in a heavier chassis is baloney, and it increases my own shop's freight costs in getting the unbuilt car kits to my customers. As well, an increasing number of kits are sold that require their detail parts sets, for example slotted rotors, tiedown hooks, etc. I personally enjoy seeing some flashy PE rotors, but to remove the slots on their plastic counterparts should I only have access to the stock kit, irks me.
I hope that my post did not really take this thread off topic. Thanks for reading!