The name “smartthings” definitely has a future For as long as Samsung is selling expensive televisions and refrigerators. 
But as company employees have said many times in this forum and elsewhere, their typical home automation customer has fewer than 15 devices and never uses any custom code of any kind.
And they’ve already announced that they are moving to a new cloud architecture which will not support the groovy programs anymore. They just don’t know exactly when.
So as far as things like MQTT integration, I agree with you: I doubt if smartthings will continue to put many resources towards anything that enables that, other than an REST endpoint integration.
But as far as an app-enabled Internet of things that lets you tie simple lighting to your television and your smart washer, I expect that to be around for the forseeable future. But as @dparker said, we will see. 
( also, as he said, the current hubs are only officially supported in the UK and in parts of North America. You can certainly buy the products from Amazon.co.uk They aren’t warranted or supported yet in other parts of the EU, so that’s not surprising. And you definitely shouldn’t have bought one from the US, as it will have the wrong Z wave frequency. Unless you were just buying Zigbee devices, and again, they should be less expensive from the UK. )