I think it depends heavily on what kind of work the writer is doing. For basic articles and general content, a relatively modest computer can be perfectly adequate because most of the work doesn't require much processing power.
Things change when the work involves large documents, image or video editing, multiple applications, or having dozens of browser tabs open at once. In those cases, better hardware can make a noticeable difference.
I suspect many writers also prioritize spending money on things that directly affect their work, such as software, research tools, or a good monitor, rather than buying a high-end computer simply because it's available.