It's difficult to measure the value of a brand, and most companies don't bother. It's expensive, because you have to pay actual people to talk to other people in a systematic way, over a long period of time.
Brand awareness is the measurement of the degree to which potential customers know that your product or service is an option when they are ready to make a purchase. You can't measure it from your marketing interactions alone, because the data set of your interactions is biased toward potential customers who are already aware of you. You can only measure it by performing statistically valid sampling of potential customers. The business purpose of measuring awareness is to help you find customers who have never interacted with your brand.
Brand affinity is the measurement of the degree to which potential customers have an emotional attachment to your product or service. A good shorthand is the degree to which a potential customer thinks of themselves as a "________ person." Think of a dude in a pickup truck saying "I'm a Ford guy, they've never let me down," or a person who won't even look at a phone that is not an iPhone. Again--the only way to measure this is by performing statistically valid sampling of potential customers. Measuring your marketing interactions alone will give you an artificially high measure of your affinity.
Design standards are important to both awareness and affinity.
A standard look helps the customer make mental connections between all the various times they've been exposed to your brand--this raises awareness. Comic Sans is not necessarily bad for awareness as long as you use it consistently in an intentional way. Randomly varying your fonts is bad, though, because it makes you "look" like several different brands, which means you will need to deliver more interactions to raise awareness.
Comic sans also might harm certain affinities, for example along the lines of being "sophisticated" or "beautiful." If a customer wants to think of themselves as sophisticated, they will seek brands that also present themselves that way. You're not going to see Mercedes Benz, which depends heavily on affinities of sophistication and elegance, using Comic Sans. You might see Scion, which depends on affinities of quirkiness and irony, use it. But again, the point is to be intentional.
Companies that are good at branding tend to be good either because they measure it compulsively (example: Proctor and Gamble), or because they are good at making internal opinionated decisions that stick (example: Apple).
Either way, the day to day operation of a strong brand does indeed look like a few people within a company telling everyone else what they can and cannot do with design.