Eddie Howe has told Newcastle fans the dream of a trophy-laden future has not necessarily died but warned it is going to take “a lot, lot, longer” to fulfil. He admitted he did not know whether he would be the manager in the 10 years or so now needed to lift the club to the highest echelons.

After a month-long pursuit of a £65m deal for Crystal Palace’s England defender Marc Guéhi ended in disappointment, Howe was left with only two outfield signings. It is fair to say the arrival Lloyd Kelly, a free defensive recruit from Bournemouth, and William Osula, a £10m forward from Sheffield United regarded as one for the future, has underwhelmed supporters.

“I’m not going to sit here and say it’s been a brilliant window,” said Howe, who lost his talented young midfielder Elliot Anderson to Nottingham Forest in June as Newcastle struggled to meet profitability and sustainability rules (PSR). “We haven’t had the window we wanted, there’s no denying that.”

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Asked if his squad was weaker than at this time last year he replied: “You can make an argument for that. I’m not going to fight you too much on that.”

Although there has been turmoil behind the scenes with the former co-owner and key director Amanda Staveley stepping down in June and Paul Mitchell, the new sporting director, arriving only in July, Howe primarily blamed PSR for the transfer inactivity. Newcastle’s commercial revenue streams have not yet caught up with their ambition and the regulations prevent their Saudi Arabian ownership from investing in players as heavily as hoped.

Howe agreed the transfer stalemate “probably made it a bit more difficult” for Newcastle to re-enter the top six and acknowledged the heavy spending of rivals, including West Ham and Brighton, represented a worry. “If your competition are improving and getting stronger and you’re not, that’s a huge concern,” he said. “But again, we’re in a difficult situation regarding PSR and that is the major problem.”

It all seems a long way from last summer when Yasir al-Rumayyan, Newcastle’s chairman, spoke of making the club “No 1”. Howe did not disagree. “I think when PIF [Saudi Arabia’s Public Investment Fund, Newcastle’s majority owners] took over, the landscape was different,” he said. “A lot has changed in terms of PSR and our need to comply with the rules to prevent a points deduction.

“That impacts the ability to progress the club as quickly as maybe they wanted to. I don’t think the dream dies necessarily, it just takes longer. We have got to build our revenue streams, bring more money into the club. This is the biggest thing we need to focus on in the next 10 years.

“Whether I’m [going to be] lucky enough to see any of that, who knows. The dream is not over, it is just going to take a lot, lot, longer.”

With Howe resistant to selling Alexander Isak, Bruno Guimarães or Anthony Gordon, plans were quietly abandoned to sign a right-sided centre-half, right-winger and central striker.

Instead every bit of available cash was directed towards centre-half, with Guéhi Howe’s preferred candidate. Newcastle’s manager denied he had instructed Mitchell to ignore other potential central defensive signings. “It’s never been about one player,” he said. “It can never be, because as soon as you’re in that position, then you’re negotiating strength is over. We’ve tried for several targets but it has to be the right player and there isn’t an unlimited number.”

Asked whether it might have helped had Mitchell been in post earlier, Howe said: “Possibly, yes. But we’ll just have to deal with the reality.”

Despite accepting that this was probably the most personally “hands-off” transfer window he had experienced as a manager Howe was careful not to criticise Mitchell and the hierarchy. “My happiness against what we’re able to do in the transfer market are totally different things,” he said. “I’m enjoying my work. I’m happy.

“But it’s a challenging period, no doubt about that. I’ve said all summer that I’m not involved in negotiations for players. It probably has been my most hands-off window. The whole structure of the club is different. There are different personalities and different ways of working. But that’s not necessarily a negative.

“My job is to continue to do the best for the players we have here. There’s been some unsettled players [at Newcastle] but the closure of transfer window will bring clarity and common purpose. We’ll just have to crack on regardless and try and have a great season while learning the lessons of what’s happened.”