You kinda told on yourself. Long story short, if you didn't have the old clutter in your shop and if the tools you did have were operational and able to make money, (even if it not alot of money) it sounds like she would be supportive of updating a broken machine. But to her, this is not updating a broken machine. As a woman and wife, she sees your old machines as expensive waste and clutter that knows no end.
You could do yourself alot of good by going through your entire shop and purging EVERYTHING that is just clutter. Top to bottom cleaning, even if it's painful. Old, big heavy machines included. Lots of runs to the scrap yard, even with the low prices. Organize shelving, hang a couple lights, sweep the floor and look as if you take this serious.
It's more about making a clean start and get you focused on starting a shop. A break from your days as a hobbies and man cave decor. It will demonstrate seriousness and commitment to your wife that you are not just adding more sh!t to your boneyard.
