Neither is a great indicator for companies that are experiencing significant growth. ARM Holdings has nearly tripled revenue over the past decade. So you have to weight future growth, as well as potential future market opportunities.
ARM + nVidia can be a powerhouse combo, especially in the cloud/server market.
NVidia is already an ARM licensee. What does owning ARM holdings give them besides a massive amount of debt? They could license everything ARM owns for decades for less than this buyout would cost.
If I sell 100 lemonades per day and can't pay my rent, yet my neighbor sells 50 lemonades but manages the business in a way to pay his rent and a salary, how can my business possibly be more valuable? It's a silly example but I don't think it's far fetched. Similarly, Apple is worth far more than 20% of the phone market despite having a grasp on only 20% (give or take, I don't recall the exact number) market shares. There's a reason companies aren't valued based on revenue.
But its definitely not in any financial metrics. If you own walmart for a year, you'll make around 4 billion, while if you own Google, you'll make around 7. And Google is likely going to be growing faster than Walmart.