Why did Apple remove the “Early, Mid, and Late” parts from the Mac models?

We are other end users like you. We cannot know why Apple does or does not do something. You can ask Apple but:

• they will not see you question here
• they have historically been very closed-mouth about explaining decisions they make

From observation, I see that Apple have settled in on a schedule of releasing a new version of an existing model no more than once a year. When I look at lists of older Macbook Pro versions, the modifiers are usually only used in years where they introduce significant changes in mid-year. Example from the MacTracker database:

So that's all we can offer—our observations.

PharynxWhiteLuxray wrote:

So one small detail that I noticed is that starting from like 2016, Apple has removed the Early, Mid, and Late parts of the Mac model names. For example, you have a 2018 MacBook Air, but it came out in Q4. Even more confusing, you have two 2020 MacBook Pros. I feel the Intel one should be called the Mid 2020 MacBook Pro, and the M1 called the Late 2020 MacBook Pro.

You can submit your Apple Feedback here: Product Feedback - Apple

They are just product names, that's all. My guess is that Apple named them that way when they were releasing multiple different models in a given year. Not so much anymore. It could also be asked why Apple even used the "Early, Mid, Late" naming in the first place.

PharynxWhiteLuxray wrote:

Even more confusing, you have two 2020 MacBook Pros. I feel the Intel one should be called the Mid 2020 MacBook Pro, and the M1 called the Late 2020 MacBook Pro.

FYI, Apple does distinguish between the two 2020 models by noting "M1" in the model name for the Apple Silicon M-series.