When trees are in among other trees, they have to use most of their energy to grow tall and straight to get as much light as possible.
When a tree is out in the open, it can get more light by spreading out and not shading out any of its own branches. So the same tree grown in different places will look different.
If you keep pruning the lower branches, the trunk itself can get thicker and stronger. It encourages canopy growth, but bigger/wider canopies don't necessarily translate to vertical growth. Removing the two lower branches will help redirect growth to the upper canopy. It leads to epicormic growth causing a few new long, streight and usually vertical growing branches to form.
If you want the tree to grow taller, remove one of the codominant leaders, fertilizer twice a year with a slow release fert, auxins and giberrellins are the two main hormones associated with tree growth, and give supplemental water in the summer to help prevent stress. This will make your tree grow taller.