True and if the question was just "do we need to upgrade De Gea?" then I would think the answer is very obvious to all but a few. But it's more complicated than that.
Pep changed goalkeepers as soon as he landed at City. But he had inherited a team that already had KDB, Sterling, Fernandinho, Aguero, Silva, Kompany, Zabaleta, Clichy and Yaya Toure in it, even before he embarked on that summer's €200m-ish spending spree of which signing Bravo was just a small part. And even then he hadn't fully fixed the GK position at that point, with Ederson arriving the following year as part of another near-€300m splurge. Meanwhile in Liverpool's case Alison was obviously a massive and key signing for them. But his signing came at a point where they had already reached a CL final with all of Salah, Mane, Firmino, VVD, TAA, Robertson, Wijnaldum and Henderson in place in the starting eleven.
In other words important though bringing in the right goalkeeper was for those two sides, they still came when they had already addressed nearly all the outfield problems first. So if the argument is that with limited spending available to us this summer we still need to focus our resources on other outfield players and punt the goalkeeper issue ahead, it seems a fair one.
If people genuinely think we're just one more summer from potentially winning major trophies then I could understand them being disappointed at De Gea staying, but I don't. Regardless of what we realistically do this summer I think we're still another year from that point. So with that in mind I don't think another season of De Gea is a massive issue, even if it isn't my preference.
We still need to sign another goalkeeper of some description if De Gea stays given Butland is on loan, Heaton's contract is expiring and Henderson doesn't want to be here. So we can still hope for some cheaper buy who can at least challenge De Gea.