While these companies are big in every sense, they are not load bearing structures of the economy.
What I mean is that they are big, but say Google fails overnight. None of the phones work, none of their services work. There will be short term pain, losses and perhaps some economic impact too. However, the world will move on relatively quickly. There will be another tech company, or a bunch of companies to replace it. There will be new areas of economy opening up to competing products and services. Youtubers will move to platforms like Twitch, email gets moved to Hey (perhaps?), communication moves to platforms like Zoom and what not.
In a few months or perhaps a year, hardware makers will pivot to a new OS, new services, new products. Business will go on, with or without whatsapp / gmail / what not. Credit flow will not stop, businesses will not stop producing goods and services. If a business depends on Google for distribution of it's services, it will eventually find other ways to do it, perhaps through twitter, or email marketing or SMS or what not.
Coming to data collected over the years. Lets say all the data google ever collected gets deleted this instant. The most hurt people are the advertisers, who will start buying generic, non targeted ads for some time and then slowly move to other platforms.
However on the flip side, a company like Google has very real power to influence public thought, manufacture consent, hide facism, nudge elections, lobby congress for unfair playing grounds, etc.
Companies like Google, Facebook & Apple are big, but in a lopsided way. Too much power to do harm, but not really a 'catastrophic' effect on daily lives of people, in the long term. They are important, but not structural. They provide jobs, but are not irreplaceable. Their power to do good is substantial, but their goal to increase shareholder value comes first.
In my view, big tech companies ought to be churned, by force if necessary, to prevent monopolistic or oligopolistic entities.
Imagine what havoc Facebook can wreak with society, if it actively starts promoting one political spectrum, and suppresses the other. The sad part is, it may already be doing that and we just can't damn know.