As a ‘normal’ internet user (who with respect to myself is no expert on networking) it would be a strange Internet where suddenly there are two WANs isolated from each other, if hosts are choosing not to pay to have an IPV4 address along with the free IPV6.
Two WANs is effectively what you do get with dual stack. The protocols are ships that pass in the night.
However, "hosts are choosing not to pay to have an IPV4 address along with the free IPV6" is never going to happen (where "never" means "not in the next 20 years", which is forever in Internet terms)
Content is about money, and money is about selling things, whether that be products or advert impressions. If you cut off a proportion of your customer base or your advert eyeballs, you cut off a proportion of your money. It simply won't happen.
More importantly, there is no shortage of IPv4 addresses at the content provider side. They have been sharing IPv4 addresses for years.
Sure: if you run an AWS virtual machine you now have to pay (a tiny amount) extra for an IPv4 address. But it's nothing compared to what companies pay for a recognizable domain name, or even for the VM hosting itself.
In any case, most websites these days run behind a CDN like Cloudflare or Cloudfront or Akamai, and just share their IP addresses.
That is: you could run your VM in Amazon on an IPv6-only address, and stick a CDN in front of it, and then your content is visible to both IPv4 and IPv6 users. Job done.
The reason for running dual-stack at the consumer side (i.e. home ISPs) is partly to be "ready" for some unspecified date in the future when IPv4 might be turned off. It also avoids the overhead of NAT (which is small for consumer users), and enables some applications like gaming and server hosting which work better when not behind NAT.
But if you don't do any of these things, you won't notice any difference.