but that does not imply that business damage and business sabotage are only employed to eliminate rivals.

Veblen sez otherwise. Refer to text, exerpted above or other, if you would to illustrate how "businessmen" or trade unions damage or sabotage their own going concerns.

This is an institutional constraint [sic], which was not entrenched at the time that Veblen was writing.

"Institutional constraint" is another euphemism for statute(s), prohibitive or affirmative state sanction of business conduct. Veblen's text would seem to contradict a retrospective claim, such as yours, that neither prohibitive nor affirmative antitrust statutes were "entrenched" [read: enforced?] as of 1904. Or that he was unaware of prohibitive or affirmative antitrust enforcement up to and including 1904.

The landmark Sherman Act of course established federal standards to test anti-competitive business conduct in 1890 (you may want to review Veblen notes to the text). Prior to that act, one, sufficient schooled in Anglo or Black's jurisprudence, may argue that private actions ("litigation") among firms enforced "institutional constraints" on conduct alledged to restrain trade at least in the US from the 1850s.

English courts generally let restrictive contracts stand because they did not consider themselves suited to judging adequacy or fairness. Over time, courts looked more closely into both the purpose and the effect of any restraint of trade. The turning point came in 1711 with the establishment of the basic standard for judging close cases, "the rule of reason." Courts asked whether the goal of a contract was a general restraint of competition (naked restraint) or particularly limited in time and geography (ancillary restraint). Naked restraints were unreasonable, but ancillary restraints were often acceptable. Exceptions to the rule grew as the economic philosophy of laissez-faire (meaning "let the people do what they please") spread its doctrine of noninterference in business. As rival businesses formed cartels to fix prices and control output, the late-eighteenth-century English courts often nodded in approval.

May I remind you that I am quoting Veblen, and anyone may take a turn to excerpt the text that illustrates his or her intepretation(s) of his keen, novel analytical insight on scale efficiences of "business" motives, accounting, and credit strategies.

Incessantly questioning or ascribing value judgements to my motives is beside the issue.

Diversity is the key to economic and political evolution.