From my Dotabuff profile, my oldest game was one played nearly 2 and a half years ago. It was a 35 minute long bot match where I played Enchantress, and I bought Urn, then Scythe. We didn’t have Truesight data then, but I’m sure I was in the jungle until I noticed the match was over (I had zero tower damage). 1865 games later and counting, I’m left with 5 heroes I have never played: Earth Spirit, IO, Lion, Winter Wyvern, and Chen. I never gave them a chance. How could I have dismissed them without even trying it (also: how can Snith play over 2,600 games of Chen)?
It’s not like I made a deliberate choice to never play those heroes. I don’t queue games thinking, "this will be another game I refuse to accept IO as a hero." Face it: who really picks heroes based on draft over ones that you just feel like playing? I can't help if feel like playing 100 games of Storm Spirit.
Why do we ignore certain heroes and obsessively pick others?
One of the biggest reasons is the meta. The spot light on strong heroes leaves others in the shadows. How do I have time to play Enchantress when in the picking screen I’m busy hovering over Juggernaut, Axe, Troll, or Sniper? It’s a consequence of the All Pick mode. If I’m playing ranked and I’m playing to win, I’m going to pick the strongest heroes. And if doing so I lose a piece of my soul, so be it. +25 MMR.
By consequence, the least picked heroes are weak (in pubs). This isn’t always the case—Chen, Batrider, Broodmother, and Enigma are some of the most neglected heroes—but if pub players drift towards the strongest heroes, they’ll flee from the weakest ones. Sometimes, the heroes are weak because they require a certain level of micro, such as Beastmaster and Brewmaster, that becomes a barrier for players. Other times, they are heroes that require a level of coordination that’s a high order for a randomly assembled team of players. How often will you get a good IO dual lane to work?
Aesthetics. I am tempted to also say cosmetics. We're currently in a feedback loop where the most popular heroes are the ones that get more cosmetics, which in turn makes them more popular. Believe it or not, Crystal Maiden was still a fairly popular support pick before her arcana. Sometimes we choose based on how the hero looks more than how it feels, which explains her spike in popularity before people realized a swimming dog didn't change that your movement speed is slower than dirt. It made me think: what would happen if we took the skill set of a popular hero and put it in another hero's body? Like a Dota Freaky Friday or Trading Places. Switch Queen of Pain and IO for a day. IO is now a mid lane staple with poor late game scaling, and most importantly: no cosmetics. QoP has a global teleport and a tether dynamic that requires a close buddy. Wouldn't you want to sidle up to that hero now?
We have comfort heroes. This is like me growing up on McDonalds and Little Caesars and being unable to refuse their pull whenever I drive by them. Dota asks us for a time commitment that can last over an hour, and it can be a taxing experience. Do we want to go through that experience with some new hero we’ve never played, or do we go back to the ones we know? Winning certainly is fun, but it can't be the only reward since in my case it's only happened about 53% of the time--60% if I played Storm Spirit. I don't care if I win or lose. Sometimes I just want to be a jovial, pot-belied, old man for an hour.
Take a look at your heroes page. What are some of the heroes you never played and was it a deliberate choice? By the way, congratulations if you've played all the heroes. I don't think I'll ever bring myself to picking Earth Spirit, unless I random him twice in a row.