One aspect of the investigation claims that tech companies are stifling competition and that the big names are monopolistic. I'd argue that's as far from reality as possible - it's never been easier to start a tech company, and the barrier to entry is extremely low. You know a market with a high barrier to entry, and literal laws preventing new competition? Internet service providers. Investigate the ISPs instead.
The second aspect of the probe surrounds concerns about personal data and its aggregation. But why bother investigating how Google et al are handling this data when there are clear offenders who have behaved with gross negligence and suffered no consequences (Equifax)? If those companies are not investigated, what possible reason could there be to investigate Google (who have not suffered a large-scale data breach) other than politically-motivated harassment? You know what would be more productive than investigating big tech companies - passing actual legislation like the GDPR to set up a framework to prevent the kind of privacy issue these legislators are supposedly concerned with.