You’re partially correct, prices did go up, in part due to increased specs/technology.
The far bigger driver behind the prices is the amount of value the £ lost since 2011 though, as well as other political factors. You can see that quite obvious in other countries, for example germany.
A new Golf VI in 2011 cost (base model/engine) 16500 euros. The new Golf VIII (base model/engine) today cost 19800 euros. An increase of 3000ish euros, in line with technology upgrades etc.
The Golf VI (base model/engine) in 2011 in the UK cost £15100. Cheapest Golf VIII? £24430. That’s a £9000ish increase over the same timeframe.
You see what i mean? Yes, base car prices went up over the last 10 years, but that’s not the reason why they’re becoming unaffordable here. Part of that is, as you mentioned, increases in technology etc, but the majority of that is an underlying problem. If someone speaks french (mine is limited), he could check the prices for Golf 6 and 8 in france etc, i’m pretty sure it’s the same thing as in germany (going up in line with increase in spec/technology).