Astonishing. Even accepting the over-inflated asking prices of Britain in general, SA3 ($A£ ?) is a grotesque outlier. I grew up in SA3 and visit friends and family there once a year on average. On some of those visits I am joined by friends from overseas. Germany, Australia, NZ, France and America.
I think their reaction to the area explains much of the price distortion.
They find West Swansea and Gower nice enough, but would never consider living there for reasons that include: terrible employment prospects for skilled people, poor climate, too overcrowded in the tourist season, a bit tacky, a lot of litter, a cultural backwater with poor transport links, over-priced and under-sized mostly ugly houses, expensive/unpleasant/unreliable public transport.
In short it does not stack up next to where they live overseas. I agree, which is why I left for NZ years ago. Sure, there are crowd-free corners of Gower that will impress most people, but that's not the only impression visitors go away with.
Visitors see that the vast majority of the Swansea urban sprawl is much, much worse than SA3. The approach by road or rail has improved a bit but remains nightmarish. They wonder where the hell you are taking them. It puts them in mind of the poorest bits of eastern Europe where the scars of the soviet construction era remain. SA3 (Mumbles and Gower) and part of SA2 (Swansea West) seem like an oasis when they reach them. It's a relative thing. They would not choose to live in Swansea, but if they really had to, they would choose SA3; at almost any price.
As with any urban area of similar population, when you look at the most desirable bits, it matters not that the majority are on state benefits or low-skill low-pay jobs; all that matters is that some of the population are employed in the same good jobs that you find in any western city: health, education, local government, bank managers, and even a few in private enterprise: lawyers, car dealers, manufacturing - the proportion is far too small in Swansea, but that's a different issue. Overall, Swansea is downtrodden and poor but there are enough of these ever-present well-paid to hold up demand in the only pleasant part. Supply and demand operating within a niche market.
The wider Swansea urban area also includes many of the cheapest houses in Britain, and the price of these has fallen steeply. Because you don't consider living there, you don't ever post examples. I am sure many other British cities have this same distortion where a poor area makes an adjacent area more expensive than it might otherwise be, but in Swansea the proportion that is frankly, a bit grim, is exceptionally high. I'd wager that 90%+ of the population live in a house/flat that neither you or I (or most on this forum) would ever consider (no matter that you'd have nicer neighbours than in the wealthier bit).
If you were looking to buy in a poor UK suburb rather than an affluent one, say sub-£100K, Swansea would score highly because over-abundance of poor properties suppresses prices at the bottom and you get to live next to Gower, perhaps enjoying lovely views over Swansea Bay and Mumbles. Geographically, the more northern poor parts have better access to the M4, whereas driving from West Swansea/Gower to Cardiff is excruciating because you have to go along the sea-front and through the city centre first. The stop-start of the first 10km can easily consume half of the journey time. Yet some people who work in Cardiff choose to live in SA3 and commute. An extra hour per day. Paying perhaps 50% more rent or with a big mortgage. This reflects how much they like SA3, but also how much they dislike the rest of Swansea.
To see prices fall in Swansea West, you need to see those who can still afford them squeezed a bit more. Higher mortgage rates and/or cuts at the middle and top of public sector is how this can/should happen. Good luck! Alternatively, poor parts of Swansea might improve so much that pressure on SA3 is reduced. That happens when people like yourself give up on Mumbles and seek better value (and nicer neighbours) somewhere like Mount Pleasant. That's already happening to some degree. If that's not for you, fair enough, but consider moving to some other city where the median quality is much higher and there is less competition for houses that you would consider. Pretty much any other city will leave you feeling less tormented.