Why are people saying Trotsky would not have industrialised the Soviet Union? That was one of his main goals; he decried the bungling, wasteful, inefficient and incompetent manner that Stalin carrried it out, that doesn't mean he wouldn't pursue industrialisation himself. Also, Trotsky was in favour of trade linkages and technical/scientific exchanges with the advanced Western capitalist countries, not Stalinist autarky, so Soviet industrialisation under Trotskyism has the potential to go much better.
The question of a Trotskyist USSR is asked on a regular basis on this forum, many, many times, and it is an extremely fascinating question because it results in a radically different Soviet Union, world communist/socialist movement - and indeed the entire interwar period could be changed - from the Stalinism of IOTL.
There are some key members of this forum who have a wealth of knowledge on this topic, and it's always great to read their input. I hope one day someone more talented and knowledgable than myself writes a timeline on a Trotskyist Soviet Union because it would be fun and get a ton of interest from readers.