It should be in theory, but in practice it's pretty stable on relevant time horizons. There are many factors fixing such equilibria. For instance, most consumers aren't rational actors carefully evaluating purchasing decisions. Or, when they pick, they may optimize for multiple targets simultaneously. There are economies of scale that create barriers to entry for new competitors. Trust takes time to develop. Etc.
To use two relevant examples:
Audio jack on phones: a lot of people want one, but companies seem to - one by one - eschew including it, and gain on the BOM savings and getting customers to purchase additional dongles/adapters. Phones are something you don't pick based on one particular feature. A new competitor that'd like to offer a good smartphone with an audio jack will have to first match many other features of competing smartphones. They won't be able to do all that and achieve similar price point, as incumbents benefit both from established supply chains and scale. Therefore, a new offering is going to be significantly worse in terms of features or price (or both), way beyond what established companies have saved on removing the jack.
Reliability of fridges: the three most important parameters that matter for customers are internal volume, price point, and overall aesthetics. The consumers would prefer a fridge that lasts a decade over one that last three years, but such decision is somewhat beyond the calculation horizon of most people (the reasoning is instead, "if and when it breaks, we'll deal with it") - and even if it was, it's very hard to verify. A company selling reliable fridges would have to first be able to reliably signal their reliability, which is hard to do. You could try offering very long (or lifetime) warranties, but unless you're an established brand, people ain't gonna believe it.
Then there's the general aspect of customer irrationality[0] wrt. price. People without much spending money prefer cheap products. There's a phenomenon in markets that probably has a name, where a market for a product bifurcates into race-to-the-bottom low-quality but cheap products, and high-end products (often for professional users) with low sales volume and high markup. The middle - quality products at moderate prices - disappears entirely. A new competitor, wanting to target the middle in such a market, will find themselves losing to both cheap and expensive ends.
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[0] - Though I'm becoming less certain that this is truly irrational. The other day I saw some article highlighting that humans like to optimize for maximizing available options, in a way that comes close to mathematical optimum. Since in money-based economies money is, quite literally, unit of options available, this would suggest that this behavioral heuristic applies.