First of all when did I say its uninvested? The first thing a player does when they see claydol is !data its stats to determine if its a threat. I have run claydol in other tiers and he doesn't work as well as he does in OU. You could be more polite when making your statements. To oblige you though, I will make my individual points.
For starters I said a bulky physical set, not a physically bulky set.
I can't remember if these are my exact evs (not on my computer atm) but i will edit when I wake up. I will also upload some replays when I have access to my computer.
Claydol@leftovers
Careful
194 hp / 184 atk / 72 Spdef / 60 Speed
Stone Edge
Earthquake
Rapid Spin
Stealth Rock
Landorus/Thundurus I :
With knock off being such a common move, 99% of all Landorus-I that I come across, run Stealth rock + 3 attacks. (Focus Blast, psychic, earth power)
252 SpA Life Orb Sheer Force Landorus Focus Blast vs. 194 HP / 72+ SpD Claydol: 74-87 (23.9 - 28.1%) -- 95.5% chance to 4HKO
252 SpA Life Orb Thundurus Hidden Power Ice vs. 194 HP / 72+ SpD Claydol: 122-146 (39.4 - 47.2%) -- guaranteed 3HKO after Leftovers recovery
On a team with M venusaur/gyarados/M heracross its easy to predict the psychic, earth power, twave, thunderbolt and switch into claydol. I can precede to either set up my hazards or spin away their hazards. Most Thundurus-I stay in for the HP ice being unable to 2hko me.
Heatran: when going against heatran, they will !data Claydol to see its stats and damage calc earth power seeing I can't ohko. Letting them either set up rocks or toxic.
0 SpA Claydol Earth Power vs. 248 HP / 220+ SpD Heatran: 204-244 (52.9 - 63.3%) -- 99.6% chance to 2HKO after Leftovers recovery
I have killed plenty a heatrans that underestimate claydol.
184 Atk Claydol Earthquake vs. 248 HP / 0 Def Heatran: 388-460 (100.7 - 119.4%) -- guaranteed OHKO
Under normal circumstances , getting rocks up (if coupled with bird spam), the opposing player will determine rocks will outweigh the potential 63% from earth power or even set up toxic to stall out rapid spin.
Charizard Y/X:
252 SpA Mega Charizard Y Fire Blast vs. 194 HP / 72+ SpD Claydol in Sun: 229-271 (74.1 - 87.7%) -- guaranteed 2HKO after Leftovers recovery
252 SpA Mega Charizard Y Solar Beam vs. 194 HP / 72+ SpD Claydol: 224-264 (72.4 - 85.4%) -- guaranteed 2HKO after Leftovers recovery
184 Atk Claydol Stone Edge vs. 0 HP / 4 Def Mega Charizard Y: 332-392 (111.7 - 131.9%) -- guaranteed OHKO
Charizard Y will never expect a stone edge from a claydol. It will attempt to ohko with solar beam/fire blast or over predict a switch. Another instance I have come across plenty of times on the ladder.
Charizard X: if it wants to attempt to set up that's fine. Unless they have roost, they arent going to get to use Ddances boost after stealth rock damage.
184 Atk Claydol Earthquake vs. 0 HP / 4 Def Mega Charizard X: 186-222 (62.6 - 74.7%) -- guaranteed 2HKO
Granted it can okho me with flare blitz but I usually don't stay in unless I feel claydol is no longer needed. That was more for the just FYI since I have had people in 1500s attempt it.
I am not saying claydol is the most amazing Pokémon in the world but when I am making teams I often have trouble finding an acceptable switch in on the incarnates. Claydol fufills this, for me, as well as eliminates the need for rocks and defog/spinner. Having the added ground and electric immunity is also a nice bonus for team options. If a pokemon like mantine can have a niche in ou (because it is an answer to keldeo lol ) Then claydol has a niche.