>Did the yield curve invert before the dot com crash or 2008?

Yes to both. In fact it inverted before every single crash in recorded history and there has been a crash every single time it did happen.

The complication is that sometimes it's years before the crash occurs. Largely due to government deficit spending offsetting and delaying the crash.

>2) Was this thought of at those times as a recession indicator. Was it being widely discussed? Or was it off the radar?

For sure it was. It's been a known metric for many decades. Old article from February: https://www.cnbc.com/2019/02/20/a-recession-indicator-with-a...

It has been triggered twice now.

There are other metrics as well.