Sure, but the "PC Market" isn't anything like what it was. In the data centre their market share probably looks more like 20% and they have almost no presence

Sure, but the "PC Market" isn't anything like what it was. In the data centre their market share probably looks more like 20% and they have almost no presence on mobile. So yes, they continue to dominate 1 sector (and even that they aren't as dominant as they were) but that sector is now just 1 part of a market that has several significant sectors they are not dominant in. It'll likely be the same for Google -they'll continue to be the dominant search engine, but search engines will be significantly less structurally important going forward.