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Do you just sit down and other strangers join you? Or is it a table you reservs in advance with friends?
Definitely an unpopular opinion, take me upvote. I’m someone who doesn’t enjoy talking to strangers or being bothered in public spaces. If I’m somewhere alone, chances are I either want to be alone, or I’m doing something I need to do and am just trying to get it done and leave. We’re certainly not ALL perpetually lonely. Many people enjoy alone time, and you’ve listed several different places that are popular for people to go / do by themselves for that reason. 
That being said, your idea of having a designated space for people who DO want to socialize is an interesting idea. Like-minded people could convene in that area with the expectation of socializing with strangers, and those who don’t want to could go about their time unbothered. A win-win situation, if you will. >

Let me guess. You live in a city? >

I do! Right in the middle of one lol. >

Yeah that's a very city mindset to not understand the friendliness of people going past saying hello. Smiling and nodding or starting a casual chat for 5 minutes then getting on with their day. 
It's okay. Not saying it's right or wrong. .
But you've been heavily influenced by city life. >

I live in the suburb and grew up in a somewhat rural town.  And i don't want to talk to strangers.  I think it's more of a personality thing than where one lives.  Kinda like introvert vs extrovert. >

We need to bring back "third places" >

100%
The US has a serious lack of quality third places that aren’t trying to take your money at the same time. (Starbucks sorta tries but they’re also kinda expensive, and a lot of them aren’t the same after Covid) 
I like public parks as a concept but when the weather is bad the only people at them are homeless with no where else to go. Sometimes I’ll start a conversation with the homeless person anyways cause some of them have interesting stories. And some of them have a brain completely rotted by meth & no understanding of what’s actually happening around them anymore. 
I think bars in the US are supposed to be 3rd places but this does leave young people (18-20) with a conundrum of where the fuck to go to be social if all socialization/ adult events are locked behind an ID that says 21+ >

Hence why certain bars do long table and bench style seating. Its already a thing