Very true indeed! Also Huawei has got to jump on the CDMA train at some point but they've stated that they aren't hitting the US officially until 5g hits the market and again we are probably two years out from that. They will settle up with T Mobile before they officially announce they have entered the US market I'm sure or you're right, it'll cripple them. T Mobile does quite a bit of business as I guess them to be the third largest carrier I would think behind the big two.
They make CDMA phones, just not for phones which they ship to the USA. The mate 9 has CDMA. Not for usa variants though.