It's all well and good saying the money is in the Premier league, but also the transfer fees are just ridiculous too, as are the wages paid. The only sustainable way is the Brentford model. Sign young players with development potential , keep some, sell others to make more signings and gradually strengthen the squad.
That also needs a proper football structure with a business plan consistent with the above values. It will take patience, but it can't be worse than what we've suffered over the last 25 years.