The thing that gives me comfort now is that we can spend big in the event of a season like last. The worry 5-6 years ago was always that if Fergie left or we just had a terrible season we didn't have the budget to go out and spend £100m net in one Summer to get us competing again. It could have easily been a downward spiral (in my opinion), where we couldn't spend big as we didn't have the Champions League income coming in and because we couldn't spend big we couldn't get back into the Champions League.
Nowadays Champions League or otherwise we can spend big in order to compete. Obviously the perfect scenario for the Glazer's would be 2nd-4th (no bonuses) every season and a manager that promoted youth and rarely spent big. We would still be attractive commercially and would still have CL revenue coming through, whilst not spending a lot - allowing them huge dividends. However nowadays you can't guarantee 4th on a shoestring budget, as Arsenal are finding out and because our business model requires CL Football I can see a budget of £50-60m a season comfortably (with cash in the bank if the right player became available).
With our current owners we will never be a Real Madrid, which isn't necessarily a bad thing. However I think we are finally at a point where we will be able to blow other Premier League clubs (Chelsea/City included) out of the water, particularly in terms of salaries. If we stick to our current M.O. of 50% wages-turnover I predict a £250-260m wage bill in 2-3 years. Last year it was £180m so in real world terms that would allow us to sign around 7 extra player's on 200k a week.
To put it simply: our financial inertia will allow us to comfortably compete for top player's, if we want to.