The main problem in making the game more accurate in terms of when to declare an advantage or not will be the percentage of success lowering down dramatically at low level. Will players like the fact they have to wait 5 rounds to kill just one goblin? I am not sure honestly.
I guess they began implementing stricto sensu 5e combat rules but realized it would be too punishing to the pace of combat. So what's the best compromise here?
First, people are forgetting a key fact:
In normal play, you aren't playing one character.
You're playing one party.
Getting frustrated by a string of misses? Cast a spell that deals guaranteed damage like Shatter. Or a spell that relies on the enemy making a saving through. Or use a spell/ability that increases your chance to-hit like Bless, War Cleric Channel Divinity, Precision Strike from Battlemaster Fighter, etc. As shown, there are 56+ available options for character *just in levels 1-4*. But yes, those methods are going to require resources or risks. That's D&D for you.
Or accept that a string of misses is part of the game and part of the character growth process. Where is the sense of progression in character level and power when you don't have any higher to go? If you're chance to hit is always 99%+, what do you care whether you chance to hit increases by a proficiency bonus increase?