I believe it was a general guiding principle when designing most of the races. At least in terms of the Halfling, Elf and Dwarf, they have been created in such a way that, generally, if you choose a class where the attribute bonuses improve those you will use for the class, a lot of the racial abilities have greatly reduced impact or become entirely redundant as they are picked up as part of that class.
In general, each race should give you a good and meaningful bonus regardless of your class.
The only race that flat out fails miserably on this principle (not looking outside the PHB at least) is the Half-Orc whose primary attribute bonus is absolutely useless to all classes except for strength-based melee fighters and has a pretty potent ability that... can only trigger if you are a melee fighter... and the other ability allows you to escape being lowered to 0 HP which is... most useful to someone who is going to be on the front lines (in melee). It is true that imaginably any character could make use of an extra round after being reduced to 0 HP, but the first person to drop is almost always the "tank".
It is only that much worse that Strength is the second crappiest stat in the whole game, unless you are using encumbrance rules than basically Dexterity can just substitute in for Strength nearly every single instance you would ever be asked to make a Strength check plus gives you all the powerful abilities, improves your AC as well as your accuracy and damage in both melee and ranged (while Strength gives you only melee). Only attribute more worthless to an average random character is Intelligence.
In short, everything about the Half-Orc race design makes it incredibly powerful when matched with a handful of classes and pretty much the worse choice for half the classes in the game (including many things you might think an Orc should be able to be.)
So basically the caveat needs to be made... you can have a well-balanced character if you play a class that doesn't mesh with your race's attribute bonuses.... unless you are a half-orc.
But, hey-- given that playing a Half-Orc was just a suboptimal choice for every class in 1st through 3rd edition and all other races were superb at one or two classes and terrible at everything else... one badly designed race (presuming you were in fact designing on the principle that any race/class combo should be viable) should not wipe away that all the other races do a pretty good job of providing you a nice benefit regardless of your class.
