I think this is because United is also having difficulty finding a new coach. Or it could also be to give Ten Hag the opportunity for a season or two to improve the team's performance. I think in the Mourinho era United was a strong team so a few defeats could make a coach get fired. But now what can United expect from sacking Ten Hag? I think this is a wise decision made by Manchester United management because currently their focus is on improving performance and it takes a long time to do so.
Finding a new isn't a problem for Manchester united it's basically them wanting ten hag to succeed in Manchester united by giving him more time, he looks promising to them because he won their heart in his first season at Manchester united by qualifying for UCL.
I the the glazer's have discussions with ten hag and they are basically building if not with the series of poor results so far and the disappointment on the faces of the fans, ten hags job is supposed to be at threat by now but it's not looking like such probably because the glazers accepts their current fate but regardless of the building phase or whatever excuses they have, Manchester united should still come up with some results that will show that their is something to hold on to because it's currently looking like they may end the season without a trophy.