I'm one of the people you're talking about. I tried it and it had the opposite effect.
I tried to do it with the plain forms once about 15 years ago. Somehow I ended up reporting the same input twice or something? I'm still not sure what I did wrong, but I ended up getting taxed for income that didn't exist. I didn't know how to correct it. I wrote letters and called the IRS probably dozens of times. I spent more than 50 hours poring through documents trying to figure it out. I tried to find an accountant that could understand what was happening. Eventually, it went away. I'm not sure what I did differently or if the IRS just got tired of dealing with me and waived it.
I was probably doing all of this incompetently, but I could not get a "foothold". I have somewhat of a tax phobia to this day.
The problem had something to do with some independent contracting I had done that year. I just resolved not to do that anymore.
Shoot, I accidentally reported the same income twice even with turbotax once because I didn't understand what non-covered shares were. (And in my defense, the broker also didn't show cost basis on the 1099-B either, I was just supposed to know)
I forget when the cost basis reporting requirements got firmed up but there were some point where I had options from a former employer that had gone through a couple rounds of acquisitions and when I eventually sold the shares I ended up throwing my hands up a plugged in some average cost basis that was somewhere in the ballpark and called it a day. It's all pretty automatic these days but it used to often be a real mess to try to do accurately.
Yea cost basis reporting from the broker to you is better now.
Cost basis reporting from the broker to the IRS is still blank for non-covered shares though, which leads to the other common case of "forgot a page of 1099, IRS thinks it's $0 cost basis, sends bill for $10k++, but actually you owe ~$0 if you send in the correct info".
I tried to do it with the plain forms once about 15 years ago. Somehow I ended up reporting the same input twice or something? I'm still not sure what I did wrong, but I ended up getting taxed for income that didn't exist. I didn't know how to correct it. I wrote letters and called the IRS probably dozens of times. I spent more than 50 hours poring through documents trying to figure it out. I tried to find an accountant that could understand what was happening. Eventually, it went away. I'm not sure what I did differently or if the IRS just got tired of dealing with me and waived it.
I was probably doing all of this incompetently, but I could not get a "foothold". I have somewhat of a tax phobia to this day.
The problem had something to do with some independent contracting I had done that year. I just resolved not to do that anymore.