Daniel Farke has defended Norwich's approach to transfer business, insisting: "We cannot risk the future of this club."
The German insists the Canaries, who are aiming to avoid a repeat of their last two stints in the Premier League which have ended in instant relegation, must live within their means.
It comes amid criticism from a sports radio presenter earlier this week that they lack ambition and are content to flit between the top two tiers.
The club sold star playmaker Emi Buendia to Aston Villa in June but have reinvested the money, with the signings of Ben Gibson, Christos Tzolis and Josh Sargent costing over £8million each.
Farke said: "We are the only self-funding club on this level and we know this. Of course we would like to spend millions of pounds for players but it's not possible for us, we have to work with our tools.
"In the last years this club was under unbelievable financial pressure, and in the last three years we have earned more money than probably each and every club in the rest of Europe and we were still capable of getting promoted to the Premier League.
"Sometimes we have to sell our best players like Emi Buendia, but we took the money and made some great signings. It's not like we just gave this money to the bank and are happy that we have so much money – no, we tried to work with this money in order to get the best possible squad.
"It's not possible to spend £50m or £60m without earning money for us. We are not capable of signing a player for £15m or £20m, we would like to do it and hopefully one day, if we were to stay as a Premier League club for a few years, we will be able to do this. The more quality you can bring in the better.
"I'm not happy just with the Championship, I want to establish this club on a Premier League level. But we also can't risk the future of the club by doing some stupid things and if this means we can't spend as much as some other opponents we have to accept this."
Farke also promised the club would "stay awake" to the possibility of further signings in the final days of this summer's transfer window, amid reports they are interested in Portuguese midfielder William Carvalho.
Norwich are bottom after defeats to Liverpool and Manchester City in their opening two games, and welcome FA Cup winners Leicester to Carrow Road on Saturday.
Farke hopes to get Norwich's first points on the board as the Premier League prepares to go into its first international shutdown of the new season after this weekend.
"It would be great for the mood, great for the confidence and for the table, after a tough start," he said.
"There is no replacement for good results, but we know that we have faced three out of the top five from last season in the first three games, so even if it doesn't work out it's not like we will give up. We think we are completely on the right path and we will see what is possible.
"My gut feeling is that we are much better prepared than we were for example two and a half weeks ago, and we are looking forward to this game."
Norwich remain without midfielder Przemyslaw Placheta for the clash with the Foxes.
The 23-year-old Pole, who has yet to feature for the Canaries this season, is still struggling with Covid-19 symptoms.
Defender Bali Mumba is sidelined until after the international break by a dislocated kneecap suffered in the Carabao Cup win over Bournemouth. Sargent could be available after a minor glute problem but Greek midfielder Tzolis (calf) is a doubt.
