Re: you could read that two ways...
"We didnt invest enough or at least invest in the right places."
It is unfortunate that we dont know what we need to invest in until the time arrives or even has gone. Not wanting trench warfare like WW1 informed a lot of the decisions, but that was the war to end all wars. Instead of military the money was spent other ways.
I do wonder if we are doing the same now in Europe. How many countries are prepared under NATO? When Russia kicked off I seem to remember seeing assumptions that the Russians (should they invade Europe) would make great gains before meeting resistance. Watching the worry in Germany that Trump moved US troops from there to Poland.