Here are some photos of obelisks that are found in Axum today. This one looks like it shattered when it fell over:
And it looks like this one is leaning:
There are several others that look like they are leaning:
With several of these obelisks leaning in the Axum area, it may indicate that the ground is not suitable for building these structures. It is also possible that the builders did not dig down to the bedrock to lay the foundations.
I wonder if it's possible to dig them up and then dig down to bedrock to put them back. Probably not. Someone would have done it if it was possible.
Maybe they need to spend their money on horizontally oriented projects like say...planting crops.