Are there many countries in which universities pay PhD students a wage comparable to a basic job in industry?
I'm not sure how much Scotland is different from the rest of the UK, but from my experience of UK PhD funding, I'm not sure why you're worried. 

A standard PhD stipend is a little over £14,000 per year, paid quarterly. Fees are covered, and additional money can often be earned by taking on teaching or marking duties, up to about £1500 per year. Taking into account that students do not pay tax this is approximately equivalent to a salary of £17 or £18 thousand per year.

While I appreciate that circumstances may vary for different people, I wouldn't really call that 


  a real struggle to get by upon


Outside of London, that is enough to rent a decent sized one bedroom flat or share a nice house, pay your bills, take a nice holiday and still have the weekly cash to go out for dinner or drinks. In London, the stipend is increased but I don't have personal experience of the living expenses there, so it may be different.

As I said, circumstances may be difficult for some people, but most universities will have support for childcare or special needs, so unless you are trying to support a family as the sole earner, I don't think it's really a worry.