AFAIK, it's always been like this.
I'm established in my genre and self publish... Yet I took a chance once when I was contacted by somebody from a big pub who wanted me to write a series for them. I was skeptical, but wanted to find out... and you know, maybe feel more validated? I signed a contract for one book with giving them the option of first refusal for the rest. You know what I found out?
Apparently my book sold very well for them. So well, they wanted me to immediately sign on two more contracts for more books. My problem? I lost about 30-50k by going with trad pub. The rates are different, their accounting is amazingly obfuscated, they hold a significant chunk back for print runs in case of returns etc. Not to mention they priced my ebook and paperback right out of the market. There is more, but needless to say, I think I would have done much better if it had been self pub. I turned down their offer and went back to what I was doing previously.
The reason or moral of the story? Even if you sell well with trad pub, are you really any further ahead? In my case, I wasn't. Getting found out because I had a sales record that made them confident they'd make money didn't work out so well for me. I'm not anti-trad pub by the way, but it just isn't for me. I can totes see if folks don't have a strong sales record that they'd hesitate on somebody. They want to make money too, just like you and I.