These legal fees are justified given Trump's reputation as an aggressive litigator with a history of pursuing legal vendettas, and the case represented a significant threat to Orbis's survival as a company. The high costs reflect the necessary legal preparation required to defend against a powerful opponent willing to spend 750 pounds per hour on his own lawyers.
Trump's lawsuit aimed to prove what we now know to be the reality; that the dossier contained egregiously inaccurate and phony allegations that caused significant harm to the president's reputation. The legal fees demanded by Orbis were outrageously high, and the dossier itself contained unsubstantiated claims that have since been largely discredited.