NATO is a huge driver for US arms sales because they have common standards that only NATO member states have access to (or rather are allowed to have access to). NATO equipment usually needs to be developed and produced in NATO countries. Nations aren't going to procure equipment that they might only be able to use outside of NATO context (exceptions like nuclear participation apply).
This is just another piece aimed at their constituents. The US basically founded NATO. Nobody forced them to spend the money they did. It was a way to project military power worldwide. You wanna throw all of that away for some Russian money? I think this is where the MIC would get really worried.
And while everyone here knows this, this bill again paints a completely wrong picture. The only bill that was paid apart from military readiness was Afghanistan, when the US - not any other member - invoked article 5.
You wanna throw all of that away for some Russian money?
Do not underestimate the greed and short sightedness of the republicans. They don't care about anything more than what puts the most money in their pockets right now.