1/ inflation over ten years is roughly 19%. So 50% is not "slightly ahead" by any means.
2/ Residential construction cost per square foot seems like a stronger candidate, with a roughly 35% jump nationwide over that time period (remembering that this does not account for inflation). Accounting for inflation that's essentially half the price increase.
3/ Neither of these factors, if they fully explained the value increase, would support the claim that regulation is to blame.
The point is that the 50% increase is the baseline appreciation or in other words the increase due to everything but regulation. Things like natural inflation, construction costs, etc. A rate above that is likely due to supply being constrained by regulation (or at least that's what the GP argues).
That's only slightly ahead of the general inflation rate and might simply match the price increase in construction.