An expected retort might be "But consumer IP addresses are subject to change." True, but sometimes a "static" IP is non-negotiable. For example, in the past if one subscribed to ICANN's zone file access program, which is public information open to access by anyone, not only university libraries or corporations, a static IP address had to be provided. Of course one could use a consumer IP address because those can change infrequently, sometimes on a timescale of years. If it ever changed then one had to execute a new agreement. Perhaps the requirement for a static IP has been dropped but I honestly doubt it.
Rate-limiting/access control by IP address is common and straightforward.
However so-called "tech" companies have shown they cannot be trusted when collecting information from users. For example, Twitter and Facebook each claimed they were requesting phone numbers from users for "security" reasons but it turned out they were using them for commercial purposes.
What would be the point when your search history would just be a liability? That is the whole point of the paid search business model.
[1] https://kagi.com/privacy