It might happen in less than ten years, but...
If you read Ms. Allen's actual statement, it says that winding down estates of the complexity of her late brother's
can take ten to 20 years. She doesn't say it
won't happen in less than a decade.
However...
The law from 1997 that provided the funding for Seahawks Stadium (later Qwest Field, then CenturyLink Field, now Lumen Field) contains a provision that says that if the Seahawks are sold before May of 2024, the state of Washington gets 10% of the proceeds.
So there is a very strong financial incentive (hundreds of millions of dollars) for the Seahawks not to be sold at least until May of 2024.
Click here for a recent article about this.
Rumors about the Seahawks being up for sale immediately can be discarded as extremely likely to be false because of this. The team will almost certainly not be sold before May of 2024.
However, the trust
does specify that the pro sports teams must be sold at some point. On the other hand, Ms. Allen states that there is no timeline specified.