Well, the only reason I have a 7.62x39 is the cheap, fun SKS I bought. I'd certainly NOT chose that caliber over my .308 for deer hunting and have no plans to rebarrel my M7 for that round.
If you enjoy hunting deer with minimal calibers, fine, but my gun cost no more in .308 and I don't see any advantage in LESS power or range.
Same would go for a choice in a bolt .30-30 or a .308. Now, I prefer my light, short, handy rifle in the short action .308 caliber to a heavier long action gun in .30-06. That's the point of the .308 as I see it. There are short action short magnum rounds now days, but my .308 works just fine for what I do. I have a big, heavy 7 mag if I wanna kill something big. I don't see buying a new gun every time a new short magnum comes on the market. The .308 is available everywhere the .30-30 is and in more variety of loads, even mil surp. The only advantage I can think of for the 7.62 shooter is cheaper mil surp. I handload my .308 anyway, but it's a very popular round on the gun store ammo shelves. And, no, I've yet to find the 154 grain 7.62 stuff, will likely have to order some soon. I really think it'd work better on hog size critters than those wimpy little 123 grainers. It's called sectional density...look it up. the higher the number, the better the penetration on heavyish game like big hogs. A big hogs gristle plate is a little harder to penetrate than an enemy's skin. Heck, when I'm specifically after hogs with my .308, I shoot Barnes X bullets. Are there any controlled expansion bullets available in 7.62x39? I think not.
The .30-30 is a great choice in lever guns (the original question was "why no bolts"), but the .308 and other rounds like .30-06 or even short magnum rounds far out class the old thuddy thuddy out of a bolt gun of similar size. The lever guns are handy, light, quick, and all you need for woods hunting and that's the niche. I have done a lot of west Texas and New Mexico open country hunting in the past and out there, the bolt gun with longer range calibers pretty much rules. You don't see many 94 Winchesters out there, though they do exist. You just gotta get closer with the .30-30. Those cross canyon shots are out of the question. I've never even been to Pennsylvania. I guess it just matters WHERE you hunt, but if I hunted Pennsylvania I'd still want my .30-30 in a lever gun, personally. Why put it in a bolt gun? It was designed in a lever and that's really where it shines.
They both will kill a deer easily within 100-200 yards. What the hell is everyone argueing about?
Read the question. The arguement is about "why there are not .30-30 bolt guns available". It wasn't "why is the 7.62x39 marginal for big hogs" or "would your rather hunt with an SKS or a 94", nope. It's why isn't there a .30-30 bolt gun and the reason why is there are better calibers and the .30-30 was MADE for handy, light, excellent little lever guns and that's why it's a popular caliber in the first place. In woods hunting, especially still hunting in woods, the lever gun would be my first choice and probably in .30-30 Winchester. But, I mostly feeder watch with my bolt guns out of a stand here in Texas anymore with an occasional trip to the west where I spot and stalk the canyon ridges (I just love to hunt the west).
JMHO, of course.