Space savers are fine for what they are. A spare.
Not having a spare wheel at all is terminally stupid and I would have been completely stranded without a spare twice in the last 6 months with the Mundano, where I had 2 sudden blowouts which wrecked the tyres.
I agree with you. Which worries me
What you want is a wheel and tyre that matches the four on the car(different sizes front to rear are another issue).
But they're big and heavy, hence space savers.
Modern cars use such large diameter wheels and tyres that there often isn't room anywhere in the car for a spare, so they came up with the puncture repair kits - which rarely work.
The alternative is then a runflat tyre. These have three issues: they've really stiff sidewalls so the ride suffers, they're much more expensive, and they work too well. They work too well because they don't look flat and the car still drives, which means that lots of drivers ignore the TPMS warning light until they've carved through the sidewalls and the tread comes off. This is clearly the fault of the tyre, not the cretin who drove on a puntured tyre for 700miles.