A couple of things.
1. IPv4 is not scarce if you are simply talking of available IP space.
You can get almost any allocation size any day of the week. However, it may be ‘scarce’ at certain providers who have limited IP space from the RIR and cannot afford to pay the $50.00/ip+ rates to purchase more.
2. It sounds like you’re doing SEO based on the OP.
Yes, this method works the same now as it did back in 1997 when I first started BUT for this to work, you have to set it up properly. This includes linking strategy, different registrars (if using the same registrar, then you need different accounts even if private WHOIS), dedicated IPs for each website and such. As others have stated, the best way to do this would be multiple cheap providers who will give you a dedicated IP. However, there are others who have a VPS and multiple subnets and it will work as long as you are making sure they all look and operate independently.