It's easy to grow fast while borrowing heavily, and that should be taken into account when looking at growth curves for various economic regions. Oil prices have also dropped from around $100 to $60 iirc.
2008-2018: total US debt (government, corporate, household, non-profit orgs) increased almost 9% from ca $68.1T to $74.1T, if you trust the numbers (https://www.nwcapitalsolutions.com/project/us-deleveraging-a...)