Okay. I've given up providing proof to people who don't ask for it because the majority of boards users ignore it anyway, so it's not worth my time. Since you asked for it, here you go.
The top 20 most picked top laners in Plat+ are, in order

Source: https://u.gg/lol/tier-list?role=top
Now, if we look at each individual champion's item purchases and do not factor hybrid damage/defensive items (except Sterak's. We'll count Sterak's as a pseudo tank item for now.) 7, or 35%, build pure damage
https://u.gg/lol/champions/teemo/pro-build
https://u.gg/lol/champions/mordekaiser/pro-build
https://u.gg/lol/champions/vladimir/pro-build
https://u.gg/lol/champions/akali/pro-build
https://u.gg/lol/champions/ryze/pro-build
https://u.gg/lol/champions/tryndamere/pro-build
https://u.gg/lol/champions/kayle/pro-build
Of the remaining 13 champions, 5, or 25%, build only Sterak's as a "tank" item.
https://u.gg/lol/champions/riven/pro-build
https://u.gg/lol/champions/gangplank/pro-build
https://u.gg/lol/champions/camille/pro-build
https://u.gg/lol/champions/pantheon/pro-build
https://u.gg/lol/champions/fiora/pro-build
Still no proper tank items at all in this list. That's 12, 60%, without a single REAL tank item.
Of the remaining on that list, there are some who do build actual tank items....but at incredibly low rates.
builds
both at 3% completion rate, and full damage/hybrids otherwise. https://u.gg/lol/champions/renekton/pro-build
builds
at 4% completion rate, and full damage/hybrids otherwise. https://u.gg/lol/champions/jax/pro-build
builds
at 2% completion rate, and full damage/hybrids otherwise. https://u.gg/lol/champions/irelia/pro-build
builds
at 4% completion rate, and full damage/hybrids otherwise. https://u.gg/lol/champions/aatrox/pro-build
That's 4 champions who build tank items, but with a completion rate lower than 5%.
This brings our total up to 16/20. 80% of the top 20 build tank items less than 5% of the time....
The remaining 4 are

Garen's top 8 items are, in order,

He builds TWO defensive items. Deadman's at 43%, Spirit Visage at 12%. Otherwise, pure. fucking. damage.
As above, but for Darius, in order,

Three defensive items. The same two as Garen, both at lower rates (13% Deadman's, 8% Spirit Visage) and Righteous Glory, 5%.
The other two, Shen and Nasus, do build pretty much full tank. 1 damage item, maybe two. But can you really say that 2/20 is "most top laners building full tank"? And yes, this is the majority of top laners. There are 41 champions registered to have gone in the top lane on u.gg, and these comprise the absolute bulk of anything picked.
EDIT: And don't come back with "hurr, the majority of players are in Silver and Gold so this is irrelevant" nonsense. No one cares who's building what at low elos. I could rock into Bronze with ADC Diana and shit on people. That doesn't mean it's viable or even remotely good.