So sure, sharing an IP amongst many people may help a little, but we've already ran out _today_. There are people living right now that will _never_ be able to access the internet or make a website because of this.
One example: Digital Ocean have a cap on the number of servers they can run at one time due to the fact each droplet gets a unique v4.
V4 is dead, time for money to be spent in the right places :)