Technology executives from Meta, Google and TikTok were in Washington District Court on Wednesday to appear in high-level cases that could dramatically change the US tech business landscape.

In one courtroom, Sundar Pichai, chief executive of Alphabet, parent company of Google, took the witness box and tried to persuade a judge to go easy on the company as the court tries to decide how best to remedy what it has determined as its status as an anticompetitive monopoly.

In another courtroom, Adam Presser, TikTok's head of operations, trust and safety, was called as a witness by the Federal Trade Commission as it sought to prove similar allegations against Meta, owner of Facebook.

For Meta and Google, their decades of unprecedented dominance are at stake.

Google is trying to make the best of a bad situation stretching back to August, when US District Judge Amit Mehta ruled that the company had been illegally exploiting its dominance in the search sector to stifle competition and innovation, therefore harming consumers.

What's under way now is the remedy portion of the trial, which prompted the appearance of Alphabet's chief, Mr Pichai on Wednesday.

"The plaintiff’s proposal is too broad," he said before Mr Mehta, referring to the Department of Justice's aggressive remedy that could result in a massive break-up of Alphabet.

Among the DOJ's solutions is a proposal that would require Google to share search data with rivals with the goal of increasing competition.

Mr Pichai described the DOJ's data sharing plan as "extraordinary" and that he felt it was the equivalent of "a de facto divestiture of search", which he said was the result of many years of research and investment.

He also questioned how productive it would be to share the company's search data.

"It would be trivial to reverse engineer and effectively build Google search from the outside," Mr Pichai added.

It's not entirely clear when the remedy portion of the DOJ's antitrust case against Google will be finished, but if Mr Mehta decides to go with a stronger remedy action, it could be the beginning of the end of the search giant's reign in search, search advertising revenue and technology influence.

Since the start of Meta's trial several weeks ago, the parent company of Facebook, Instagram and WhatsApp has tried to prove that it's not a monopoly, as it has competitors including TikTok and YouTube.

The FTC, however, used various instances, written and spoken by TikTok officials, to prove that it is not a competitor to Meta, rendering the company's point moot.

“Our service is not intended for networking purposes," said Mr Presser, while answering a series of questions by an FTC attorney.

"In our view social networking services [like Facebook] are platforms for people to build social networks and relationships… the TikTok consumption experience is driven by user interests and is not dependent on social network driven inputs." He added that it might be accurate to call TikTok a social platform, but not a social network, like Facebook.

He also told the court that the China-based platform sought to dabble in making enhancements to TikTok's social network offerings, but that the company hadn't "been particularly successful" in doing so.

If TikTok or YouTube are not seen by the court as competitors to Meta, the company could be at risk of losing the trial and being forced to sell off profitable portions of its business, such as Instagram and WhatsApp.

Meta's trial is expected to take two and a half months.

Some analysts have suggested that the FTC's anticompetitive arguments might be difficult to prove amid a technology landscape cluttered with apps and social platform offerings.

Even if the FTC loses, however, Meta is still spending enormous time and resources defending itself. The company's chief executive and famous founder, Mark Zuckerberg, has not been immune from having to take the stand.

With the intense trial continuing, competitors are not by any means standing still.