I would say that is more lip service, because when the announcers talk about players, tey talk about what teams if any they were on, how they don't get a chance to improve on the practice and how the XFL gives them game experience to really improve their game.
I don't think it will happen for two main reasons: 1) The NFL is not going to want to share their pie, so to speak. If the XFL were to have an arrangement with the NFL, the XFL would probably cost more money than they would contribute. 2) Over the years the NFL system has proven pretty good at weeding ut the players that really just don't have what it takes to contribute in the NFL. There are not a lot of players that slip through the cracks and would have been great if only they got the chance.
But all that being said, I've watched 3 XFL games so far and it's not bad football. It's not great and I probably won't follow a team or anything but being sick one weekend and still recovering the follow weekend, it was something to do. Saw some big time hits, the XP system allows for some drama at the end of games and saw players that fought hard to pick up first downs or TDs.
I know... A lot of it is teams just don't want to lose starting level QB and the value for starting level QB just goes up and up and up every next year because the cap rises. Also, another aspect is - a lot of those players get those contracts after just 3-4 years in the league and their teams pay more for what they think their QB can develop into in the future than what they are now. With some of them their QB takes the next step, and with others they don't and end up being 'average-ish' QBs on high salary...
List your best QBs in the league. Anything between around 13 and 18 is average-ish... You will see that at least several of your "average-ish" QBs have been paid record setting salary at some point over the last 3-4 years. I don't get why this is such a contentious evaluation. Ask @NFLfan if she thinks their QB is anything more than an average QB in the league. The point is they are not anywhere close to elite.
Of course the Superbowl should be the ultimate goal. It doesn't mean I expect it every year or even most years. But I do think having a legitimate chance to get there should be a goal(you still need luck, health, good matchups, etc.). I don't think Dak or Cousins or Carr give us that chance, especially if you give them 35M+ salary.