> I have lingered on Brunel’s career for so long not because he was of unparalleled import to the history of the age of steam (he was not), but because his character and his ambition fascinate me.

Huh? Brunel designed many of Britain's railways and quite a number of large railway bridges, most of which are still in use.

If he had not done so, someone else would have.

The things that Brunel designed that were novel were not successful, the things he designed that were successful were not novel.

It's a good idea to note that a lot of the railways he designed were designed as very different than what they would eventually become, having had all the distinctiveness he brought to the projects removed in order for them to become commercially viable.

In the end, none of his successes elevates him above any of the hundreds of other engineers working at the same time as he did. What separates him from the rest were his glorious failures.