Every season I push into or close to P1. Tend to start P2 then work my way into P1. However, I disagree with the current system as well. Loyalty is not being rewarded at all.
Let's use your monetary example. If I had a ST for the 10 years or whatever it is, say at £400 a season, I have spent £4,000. If someone else has a ST for 8 years and has gone to 10 away games a season (again let's assume £400 a ST and £30 per away), that person has spent £5,600 in the same period. Yet the former still gets more loyalty benefits and will likely get an away ticket over the latter.
People should not be rewarded for holding a ST over x years. By all means award some form of loyalty but make it reasonable. 2 points for every season a person has held a season ticket, 1 point for every away game (just an example). In the above example we would have Person 1 on 20 points, Person 2 on 96 points. Seems more than fair to me.
Imagine your son being 5-10 years later, he would be going to barely any away games.