Whereas the system for supplying software with IP addresses should continue to remain controllable by the user.^1 The online ad ecosystem has never had full control over that system.
1. If they so choose to exercise said control. As cited, probably most users are not currently exercising that control. This allows online ad tech to operate with relative ease, at relatively lower cost.
As much as anyone loves their ad blocker (to be clear, I think they are great), we really cannot dismiss the role of DNS in ad blocking. After all, it is DNS that is being used to bypass uBO on browsers other than Firefox. The only reason uBO can achieve a 70% success rate^2 blocking CNAME-cloaked ad/tracking on Firefox is because Firefox has a "DNS API". As such, uBO can check the results of DNS lookups for ad/tracking server hostnames/IPs.^3
Of course, a user who blocks ads/tracking outside the browser by controlling her own DNS lookups also has access to those results. No API needed. (Although I think it's a great project, I personally do not use Pi-Hole. I was using DIY DNS (without dnsmasq) long before Pi-Hole.)
One solution I can see to a future where ad blocking extensions are banned is a user-controlled proxy that performs similar operations, but outside the browser.
(I make most HTTP requests for recreational web use outside the browser, through a proxy I control. For recreational web use, I do not use a major browser to make HTTP requests to the proxy. The programs that I use have no financial dependence on online advertising/tracking/data collection like the major browsers and many mobile apps do.)
2. According to the paper cited on Github page that comprises the OP.
3. According to some uBO users sometimes the uBO-triggered lookups are undesired, e.g., when using proxies/VPNs.