In terms of a long war and with no outside intervention, sure, the C.S. was likely to be beaten. This ignores that:
A) The Anglo-French were seriously considering intervention in the 1862-1863 timeframe as I pointed on in this very thread.
B) Wars are not solely determined by economic determinism; morale exists. As I also noted previously in this thread, Lincoln expected he was going to lose re-election as late as August of 1864 and the historian James McPherson notes that Northern morale was on the verge of quitting the war by then.
All it takes for the C.S. to win is one good battlefield success in the Fall of 1862 or 1864.
Which ignores the Black codes pre-dated the CSA's existence, underlying the racial animus, as well as the fact that the prohibition on Black voting rights was occurring....at the same time Confederates were killing Union soldiers IOTL. I fail to see how any of this changes.
It is indeed a meme, and the book citations I've already posted show this. I could add to them Robert Fogel's Without Consent or Contract and The Economics of Industrial Slavery and the Old South by Robert Starobin. In reality, the planters had no opposition to industrialization and the overall trends favored it; it was cost competitive with free labor and the rate of return was, in some cases, equal to cotton; overall it was not far behind. Indeed, hundreds of thousands of slaves even in 1860 were involved in Industrial or Proto-Industrial work and the overall proportion could and did show fluctuations. Case in point is the effort made to develop Birmingham as an industrial center in the 1850s by Planters.
There was no polling in this time period, any estimates of failing Union Moral were just guesses. Draft calls were filled, volunteers came forward, the army fought on, and elections were held. The anti war factions won few elections, and the army voted overwhelmingly for Lincoln. Everyone who voted for the democrats in 1864 didn't want the South to win, people vote the way they do for complex reasons. Likewise people in the North had inconsistent views about Blacks, holding racist views doesn't necessarily mean someone is indifferent to slavery. Before the war people in the North showed no support for enforcing the Fugitive Slave Act. Despite racist sentiments the North passed the 13th, 14th, and 15th Amendments, along with the Civil Rights Act of 1866, passed over a presidential veto.
Anglo/French intervention was never likely, it involved more risks then it was worth. The Union wasn't going to fold up because the British said BOO!
Southern Industrialization was more then a generation behind the North, and remained so for over 100 years after the CW. The Southern Aristocracy fought the war to maintain their planter culture, they disposed the Northern money grubbing bankers, and industrialists. Of course you can become what you hate, but where would they get the huge capital investments they needed? England, along with the other European Powers put their money into Northern Industry, and they sure weren't going to get it from the USA.