If it was just the players' fault we wouldn't be seeing the same pattern repeat itself year after year for 20 years. The issue runs much deeper than that, and starts at the grass roots level.
I keep banging on about it , but when France had the problem of under performing teams, they put a ten year plan in place to develop players from the ground up. A plan they stuck with even after an early minor disaster of blowing a World Cup qualification in 1994. They followed it through and ended up with a national team that won the Euros and the World Cup.
Meanwhile, when Strachan took over the international job he went on record with his surprise at the squads' poor technical skills and how he had to quickly dumb-down the tactics he wanted to use because the players were incapable of executing.
Once the rot sets in, it takes more then swapping in new players to fix it. The whole system needs shaking up and there has been nobody in the SFA with the courage to change it. That's how you end up with Malky Mackay as the performance director for the past 4 years. (Any idea what he does? Me either.)
We don't have the infrastructure in place to develop international teams, and I don't see anything that makes me think there is appetite for change.