Calvin did not add discipline as a mark of the true Church, since he could not get his way in Geneva. For example, he wanted weekly communion, but the city only granted quarterly communion.
Not everyone would agree with this assertion, and I suppose even more would disagree that such pragmatism, so expressed, shaped Calvin's theology concerning the marks of the church. I think one should be careful about offering such simplistic descriptions, especially with respect to a view that has been disputed (i.e. whether or not Calvin believed discipline to be one of the marks of the church).
Moreover, in a letter dated August 12, 1561 (about three years before his death), Calvin did express that he was pleased with the present frequency of the observance of the Lord's Supper in Geneva (monthly), which by the good hand of providence he was instrumental in changing...
John Calvin (1509-1564): We are very pleased that the Lord’s Supper is being celebrated every month, provided that this more frequent observance does not produce carelessness. When a considerable part of the congregation stays away from Communion, the church somehow becomes fragmented. Nonetheless, we think it is better for a congregation [to take Communion] every month than only four times a year, as usually happens here.
When I first came here, the Lord’s Supper was observed only three times a year, and seven whole months intervened between the observance at Pentecost and at the Birthday of Christ. A monthly observance pleased me, but I could not persuade the people, and it seemed better to bear with their weakness than to continue arguing stubbornly. I took care to have it recorded in the public records, however, that our way was wrong, so that correcting it might be easier for future generations. John Calvin,
Calvin’s Ecclesiastical Advice, trans. Mary Beaty and Benjamin W. Farley (Louisville: Westminster/John Knox Press, 1991), p. 96.
Calvin was able to manage reform considerably, with respect to a more frequent observance of this sacrament, and he did not build his theology of the church on pragmatism.