So will anybody ever trust the polls again?

I still don’t understand internal polling. .
I started a thread about internal polls a couple weeks ago,
But it didn’t really answer my question: how and why are internal polls different than the public polls?
They are carried out by the same companies (Gallup, etc), using presumably the same techniques.

Why do we often hear that the internal polls were more accurate than the public ones?
If it is so easy to be accurate for internal use by a specific party, why can’t the pollsters be accurate for the public?

Yes, the internal poll might ask “secret” questions that are designed to expose a weakness in the party, which they don’t want to reveal. So they order (and pay for) the poll. (maybe, I dunno, targeting very local issues or ethnic groups).And then the party might try to improve in that specific area, without letting the public know.

But most of the polls we see are done by large,objective organizations such as news agencies, Gallup, etc…And those agencies have as much of an interest in getting to the truth as any political party which orders an internal poll.
The polling agencies make their reputations–and their money!- by being accurate…So even if they are under contract with a political party and have a non-disclosure agreement, they could still run their own polls, at their own expense, and try to get the maximum accuracy possible. It’s in their own interests.

For example: right now it looks like the famous “90%” chance of winning for Biden is so totally wrong that the public may give up all interest in polling at all. I’m certainly not going to believe them in the future.So if the polling companies want to avoid bankruptcy, they’d better improve their results.

(or maybe our society has changed enough over the past 5-10 years that it is now impossible to do accurate polls. (maybe because so many people refuse to answer phone calls these days?.)