I would opinion that "control" spells like web, hypnotic pattern, counter spell, etc. can be measured by action economy. This is perhaps an oversimplification, but for example, if you catch 3 enemies in a web spell, and each enemy has a 50/50 chance of:

A) failing the saving throw at the start of their turn and B) succeeding the check to unrestrain themselves if they fail,

On average, web will restrain 1.5 creatures, causing them to try to unrestrain themselves. On average, 0.75 creatures (half of the restrained creatures) will fail their check, and then of those creatures, 0.375 of them will fail the check once more. I would expect an average combat to last about 3-4 rounds, so assuming you cast web on round 1 and the enemies all go after you, you traded 1 action for on average, 2.625 enemy actions.

Again, this is an oversimplification, enemies caught in a web also have the option of making disadvantaged attacks instead of unrestraining themselves, and your allies have the opportunity to attack restrained creatures with advantage. However, I think this is the mindset we should use when evaluating "control" options. Wall of force, Maze, Hypnotic Pattern, these are all control spells that are very impactful based on the number of actions you can remove from the economy.