It would have to be George Thomas, I think. He was one of the most capable army commanders in the war, saved the Army of the Cumberland at Chickamauga, and finished off Hood in Tennessee in 1864. Everyone forgets him, despite the fact that he was behind only Grant, Sherman, and Meade in the Union Army's seniority at the end of the war.
For Meade though, it wasn't so much the right decision not to pursue (and he did pursue, as best he could), but the only decision he could make. The I Corps was exhausted, the XI Corps was broken and demoralized, and the III Corps had been absolutely shattered. Both the I and the III Corps would be merged into other corps, and the XI Corps would be transferred west, never to fight with the AoP again.In terms of commanders, Reynolds was dead and John Newton, unproven in corps command, was running what was left of the I Corps. Sickles had lost a leg. The V Corps had been committed piecemeal, and had lost more than a few of its brigade commanders.Meade had three intact corps: the II, the VI, and the XII. The XII Corps was under the command of Slocum, who Meade had no confidence in at all, and was notorious for slowness. The II had fought hard and was pretty tired, but more than that, they'd lost Hancock on the third day of the fighting. All that was really left was the VI Corps under Sedgwick.In order to even think about mounting a major attack on Lee, Meade would have needed to rearrange his army's structure on the fly. He really did all that he could.
You can't really separate the two like that. The Industrial Revolution drove the Civil War; the Civil War helped spread the Industrial Revolution throughout the country.After all, a Southern victory in the Civil War meant that the agrarian society of the South would have still been profitable for another generation or so. That would significantly delay the industrial revolution in the South, and it would have a radically different character (being manned by slaves or slaves-in-all-but-name) when it happened.
The theory of communism speaks to people that want something for nothing, or should I say people's innate laziness. That is its appeal. The problem with the communist approach is that Marx and Engels never really specified what happens after the establishment of the "Dictatorship of the Proletariat". They seemed to assume that everyone would pull together out of a sense of brotherly love. Marx was long on pithy slogans but short on practical ideas of governance.
I sincerely doubt that this was the case. After all, the communists and socialists were strongest among the farmers and laborers; not people who led lazy lives. What the communists and socialists promised was a more radical, faster, and easier way towards the just society that the Populists, Progressives, and the New Dealers were seeking.If you notice, the communists and socialists were at their strongest when liberal movements like the Populists, the Progressives, and then the New Deal seemed to stall. In other words, they turned to the more radical party because the moderate movements didn't seem to be getting where they said they'd go. Whenever those movements enjoyed a major success or had a charismatic leader like William Jennings Bryan, the more radical parties weakened again.