Yes, we are able to buy real estate in a decent location. We live not far outside Stockholm where prices are really high compared to the rest of the country, and we had no problems buying our house.
My salary is ~twice the median income for this area, and by any measure we're at the upper end of middle class by Swedish standards.
Not far outside is a very lax definition. A 500K Mortgage (affordable with aforementioned salaries) gets you a 2 bedroom in good neighborhoods in Paris, 3 in lesser ones. Sure, if you're ready to go 20 km away you can get a rather nice house at that price (say 100-150m2 with a garden of variable size), but at the cost of commuting 30min-1hr everyday.
Anyways, I wouldn't consider someone establishing outside of an european city (esp when working there) "high middle class". If you can't afford central housing of your choice, you dont qualify.
Don't forget public transportation which is non existent or bad in many places in the US, a 30-45 minutes on a Stockholm Metro or train takes down the prices significantly. Those 300,000$ can buy you a nice semi detached and you won't need a car on a daily basis.
My salary is ~twice the median income for this area, and by any measure we're at the upper end of middle class by Swedish standards.