Second opinion re: rear wheel wobble

First make sure the rim is not bent or the spokes are not loose.
Pluck the spokes and listen for a dull twang on the loose ones.

Google wheel truning or look here
Truing Wheels
Buy a spoke wrench and tighten them in small increments not 10 turns at a time

Remove the rear wheel and take it to a bike shop if you are uncomfortable tightening spokes or balancing a wheel

Can you have the rear wheel bearings greased. and adjusted

there can be a few things that cause uneven tire wear.

one, is the tire itself. some low-end tires aren't round. you won't notice it without a motor, but get it up to 30 and it'll hop allover the place.

two, the innertube may be the wrong size. this isn't too common, but i have 26x2.3 tires, and if i run an innertube designed for the more common 26x2.125 tires, it'll get a hop in it near the valve stem because the tube isn't properly filling the tire.

three, the wheel (hub, spokes, and rim) may be out of true. if you spin the wheel, look at the rim. if it's perfectly straight, no lateral hops or radial twists, then it's the tire.

if the rim is hopping or twisting, it needs to be trued. a bike shops your best bet, unless you feel like experimenting. it's easy once you learn how, but if you have more money than patience, take it to a bike shop. most charge about 20 bucks.
it's a good idea to take the wheel off the bike and bring it to them. most bike stores don't like cheaters who use motors cause we're too lazy to pedal

if the hub is what's actually "wobbling," then it's the cones. if you grab the tire and wiggle it back and forth there shouldn't be any play in the hub itself. cone wrenches are getting harder to find, because most bike shops aren't "shops" anymore, they're "stores." but they could order them for you, or just have them tighten up your wheel.

lastly, bearings don't "wear in." they wear out.

a properly adjusted hub will stay that way for a long, long time. i've taken hubs off 80 year old bikes that were still properly adjusted.

factors like; not tightened at the factory, not checked upon installation, and improper installation are the usual causes for the cones to come loose. worse case is broken races, cracked hub flanges, pitted races, stripped axles and nuts, etc...

i think that's enough info for now...

oh, Ware's bike shop isn't there anymore is it? what about Quality bike shop? it's only been 30 years since i was there last...

Sounds like you just need to tighten up your cone nuts. Its very easy to accidentally loosen them when installing the drive sprocket on the rear tire if its a coaster brake hub. When you remove the brake arm there is nothing to lock the cone nut in place.

Don't forget to check the balance of the wheel as well.

BTW- a half inch is A LOT of "wobble", no matter which way it's wobbling.