I would argue that something else may be happening as well. While yes, Ocasio-Cortez and Warren are getting a lot of coverage and have built something of a following in the Democratic Party, there is another growth sector in the party. How did Democrats win control of the House last year? Where did Democrats capture seats and who provided them their victory margins? Democrats gained previously Republican seats last year in the suburbs—for example, outside of Atlanta, Dallas, Houston, Kansas City, Minneapolis, and the district in and around Oklahoma City. And they swept four seats in Orange County, California. It was college-educated women who turbocharged those gains. Disproportionately, many of the Democratic candidates who did well last year—winning or coming close in difficult districts—were military veterans and people from law enforcement backgrounds, particularly prosecutors. Some were no doubt liberal, but based on Republicans having previously held many of those districts, mostly not. We could throw in Kyrsten Sinema winning an open Senate seat in Arizona running a very centrist campaign.
This is not to argue that the Democratic Party is becoming a centrist party again; there is not much evidence that the center-left, business-friendly Democratic Leadership Council has been resurrected. But there may be more than one thing going on in the Democratic Party, no matter how much the media is pushing the AOC-Warren meme.