I think an important factor in the current round of rising prices is when sellers in oligopolies detect that demand is a bit more elastic than previously believed, or in other words that consumers can and will pay more for goods, the prices go up because me want more money.

I think supply chain disruptions caused prices to go up during covid and the Ukraine war, but then once some of those disruptions started to go away, sellers were like "when he had to charge twice as much for these products, people paid it; why wouldn't we keep charging twice as much? Maybe we should try three times more, see if they pay that." Nobody in an oligopoly is going to be the one to undercut, they all just match. Hence, a rising wave.