Deejay, with bushes you usually just drill the oil hole through the bush after you press in the bush but before you put the axle through, so it always lines up.
The plastic end caps could work reasonably well if they were cheap. It is like the unlubricated plastic wheels on a rotary mower: they do wear out, but you just replace them and soldier on. However it is different with a metal-on-metal bearing that is dirt-lubricated: it wears quite quickly, possibly seizes up, and is relatively expensive to replace.
If you don't use replaceable plastic bearings, the next step up is ball or roller bearings, grease points, and proper seals to keep dirt out. In cost terms, that is a very big step.
