It because of this exact technical challenge that ads nowadays appear between paragraphs in the middle content column, instead of in the right column where they belong.

never underestimate the levels ad tech will stoop to interfere in an attempt to gain even more eyeballs/clicks. your attempt to sit them at the table in the back of the room next to the kitchen was never going to be the final placement

I will go a step further and argue that all the websites we see today with dropdown menus at the top, a huge header image below it, one blob of disjointed content(?) below that, and finally the footer at the end is(was?) a direct result of the Holy Grail being so difficult to achieve outside of using tables.