Alright. There's been some flaming going on here. Please remember this is a game and forums are places for good-natured opinion.
(5542.1) I answer this question by looking at the larger goal: to have players that outplay their cost.
I agree with you, w_alloy, that older players generally do this, if you pay a reasonable price on the TL. My analysis showed that the older player was cheaper, both in the long-term and the short-term. But to my view, this isn't the whole picture. There are things my analysis didn't cover, like merchandizing revenue and the different price-to-salary ratios of players of different levels and at different positions.
You can succeed by getting old players that are undervalued because of the stigma many managers have about skill drops. But having star players with longevity on your team can earn merch/sell tix. This is hard to quantify. But it can be worth, depending on your division and team make-up, maybe $5k-$20k per starter per week-ish? emphasis on the -ish ;-). This is the factor in the game that balances (or attempts to balance) the advantage of being able to get older players comparatively cheaply.
This is part of why I suggest that managers diversify. I won't claim that I've got it all figured out, or else I would be winning the B3 championship as we speak. But I think that there are three main categories that players will fit into on a team.
1) Trainees - These players help you outplay their cost by getting better over the course of the season. This is 20-40% of your roster, since the most development comes from 1 or 2 position training. They are either long-term players-in-training, or train-for-sale players. Since they gradually get better as your team improves, you can keep long-term players-in-training throughout the development of your team, increasing the amount of merchandise they can sell.
2) Long-term players - These players help you outplay their cost by keeping fans happy, which earns you merch/sells you tix. They are good enough to be on your team for seasons in a row. And you maximize their merch/tix selling by playing them often. So they are likely starters or primary back-ups. You probably buy them when you promote and hang onto them until your team outgrows them or they are rotting.
3) Short-term players - These players help you outplay their cost by being better than similarly priced younger players and/or by being sold for a profit on the TL. They can fill out your roster around long-term players and trainees.
Then there are "rentals." These are players that are beyond the budget of the team, but are signed specifically to make a run at the post-season and dropped before the team goes bankrupt or retained upon promotion if finances allow.
It's like investing in the stock market. And you want to invest according to your goals. And there are ways to climb to the top quickly by making lots of good short-term, high-risk deals or you can make good low-risk, long-term investments for a nice retirement. I think the savvy manager will be well-positioned to take advantage of trends in the game and have assets spread (to different degrees) among the three kinds of players as well as cash-flow.
I think that the game at the lower levels rewards quick deals (and rightly so, from a game design standpoint). But I'm not convinced the same is true about the higher levels. I think at every level you need to be aware of how many players of each category you've got, and to make sure you're maxing out what you get from each type. w_alloy, this is what I was hinting at when I remarked about Gatovskis on your team. I think your roster shows that you understand the benefit of diversifying your assets.
Hope this makes my posts clearer... I agree about older players, but I see the "older player tactic" as one of a number of feasible tactics for getting good play out of low-cost players in this game.