Richard Bensel's Yankee Leviathan: The Origins of Central State Authority in America, 1859-1877 has an interesting analysis of the Republican coalition which relates slightly to what's been discussed above. I'll quote the wiki summary:
Finance capitalists' primary interest was in the overall stability of the financial system. This interest militated against continued Reconstruction for several reasons.
The potential for monetary instability as a result of Treasury incompetence made finance capitalists skeptical of state intervention in the economy. Finance capitalists supported a return to the gold standard, which would re-expose the United States economy to international influence, especially the British sterling, widely seen as more trustworthy and stable than US Treasury regulation. Finance capitalists' general suspicion toward the central state also meant they opposed practically every measure that would increase state revenue and supported tax reductions. A permanent military occupation of the South by federal troops would be extremely expensive, and would require increased extraction from the private economy, a slower return to the gold standard, and impeded the stabilization of the national debt.
Reconstruction threatened to continue the disruption of cotton production. Because most cotton exported for the international market went through Northeastern ports, Northern financiers had a strong interest in uninterrupted cotton production.
Supporters of Radical Reconstruction (notably, a Reconstruction bill sponsored by Radical Republican Thaddeus Stevens) aimed to enact a highly redistributive program for the South in order to create an economically independent base for the Republican Party. Under such a program, on the basis of loyalty to the Union, Freedmen and poor yeomen Southern white Unionists would receive wealth directly confiscated from Southern separatists. This had the potential to transform a race-based cleavage between Blacks and Whites into a class-based cleavage between poor farmers and landholding elites. At this point, it was difficult to see how this conflict could be contained in the South. Northern labor would almost certainly begin to make demands for eligibility in the transfer of Southern wealth to the lower classes, since they had remained loyal to the Union as well. This was an unattractive option for Northern capitalist members of the Republican coalition, both because of the disruptive effect on Southern agricultural production and the potential for an increase in generalized class conflict.
Bensel shows that Republican politicians representing banking districts voted closely in line with the interests of finance capital; a large part of the Republican coalition was thereby put against the project of Reconstruction and the state-enhancing measures that would have come with it, while other Northern sections of the Republican Party did not have deep enough interests in Reconstruction to constitute a veto over the influence of finance capitalists. In other words, the client-group formation path of state-building had a strong self-limiting character, wherein further state-building was stymied by this client group.
Tl;dr: the Republican coalition was split between Radicals who wanted to enact a redistributive programme in the South and those linked to Northern financial interests who feared the financial cost and class conflict blowback on the North. The latter won out and ended Reconstruction.
