To be fair not sure you can expect much more from boots that cheap.
Rest of the boot is sturdy and decent. What's the magic ingredient in a durable sole that costs so much these days?
20 years ago my grandad give me his old walking boots, they were tougher than any other boot I've known. He'd used them for decades and they were still solid, soles included. One day came back from college to find my mum had thrown them away, along with dozens of other good shoes in one of her random 'clean outs'.
I don't believe manufacturers have lost the ingredients list handed down for generations of boot manufacturers to make durable soles that don't wear thin after 500 miles of walking. If car tires had the same poor durability they'd be worn out within a week. You'd have to change them every time you went for petrol.
Its a conspiracy - make boot soles as soft as possible without consumers self-organising their own supply of decent soles. For the average consumer who averages a 10 mile outdoor trek once a week, they get a year's wear from a boot (500-600 miles ) before the soles are gone. But a serious walker can easily do 100 miles in a week.
I'm just hoping there's an alternative market, sustained by the army perhaps, for soles that aren't made of cheese.
So I have to pay £100+ just to get some soles made of slightly more durable cheese? bah. I'll rather go to the old car tire dump and cut my own soles from old tires. Tell other people. Supply them, build a community, have a net forum, youtube channel - how to DIY 100+ years worth of boot soles from a single car tire. Then see how the cheese-boot racket reacts, maybe panic and lobby the gov to make cutting soles from car tires illegal cos it breaks safety regulations.