Commercial banks love to lure us in with high rates which they then lower later on. Some of them also offer high interest but then severely limit the amount of money you can put in. The best instant access interest rate I can have with my bank is a pathetic 1.5% which isn't even paid daily. The banks also love to lock people in by offering higher rates but in return, the bank prevents you from accessing your cash for long periods. In my experience, these rates are never more than 0.6% higher than the best instant access rates and they're often considerably lower so just another rubbish "retail" offering to catch people who aren't in the know.
A lot of how commercial banks make their money is by relying on the ignorance of you and me in not realizing we could get far better rates. We may not earn interest on cash we have sitting in a current account, but unbeknownst to us, the bank is of course quietly earning at least 4.75% on our cash. I don't know about you, but I think that it's outrageous that my bank is offering me a measly 1.5% of the 5%+ they're earning on my cash when they know very well that there are options where I can earn 4.6%+. They're hoping I don't know about those options, so too bad for them that I do.
£276bn is held in bank accounts which earn no interest for the end user. Naturally, the banks leech interest off all that money. But the ugly truth is that for every bank account earning no interest, there are probably several earning measly "retail" rates below the 2.5% approximate rate of inflation. I suspect that the proportion of people earning closer to that optimal 4.6-4.9% rate on their accounts is shockingly low. This can only be changed through greater awareness of zero/very low risk (mostly FSCS Protected) fintech baking products which blow the retail banks out of the water, and expose the free ride they're getting on too much of our money.