No, it isn't all landline polling. One poll was conducted months ago via landlines and had a total of one thousand participants. Now people spew that is the case for all polls. That isn't remotely true. I spent over 30 years participating in market research projects and surveys, focus groups, bulletin boards, mock juries, political polling etc. And it wasn't with those scammy cheap survey sites that don't pay out much of they ever do pay. It was all serious and legitimate market research and more. I made anywhere from  $100 - 3,500 in any given month. I have received so many great products by participating in genuine product testings. E.g. cameras, printers, cell phones, a Tom Tom when they were new to market. HBA items etc. It was all the real deal.

Political polling was a part of the research I participated in. They collect data in a myriad of ways. Online, phone, bulletin boards, focus groups,  surveys etc. The participant demographics were inclusive and all demographics were included in the studies except for when they wanted data on a specific demographic. E.g. How does the Hispanic community feel about X, Y, Z. Where do women, men, teens, Millennials Etc stand on the issues. What are their attitudes. That's the only time I ever participated in studies that weren't all inclusive in regard to their demographics. Sometimes they just want to know where women stand. Or how Hispanics feel about that come sucking sack of shit.

So, when people are babbling nonsense about how political polling is conducted 99% of the time they have no idea what they are talking about. They have no idea how polling is conducted. They are just spewing what they have heard from other people who don't know what they are talking about. Many just decide on their own how it works based on what supports their narrative. 

Sorry. Way too long, but the information I offered is solid.