More like why put a Pac-Man in the game room that makes $3 a day.
people everywhere get greedy and optimize for the short term gain all the time. For example, I dumped a lot of money into those quarter shovers hoping for a payout... once. I put a lot of money into a crane machine... once. They probably each got $5 out of me, exactly one time each. There was a line of like-minded idiots behind me waiting to do the same on each occasion. Perfect example of a short term gain ($5/player), at the expense of long term loss (I'm NEVER playing again.)
It is very hard to see the long term loss when the short term gain is so high, and virtually every product and service offered today is optimized for short term gain, which is much, much smaller than a long-term gain would be. Amazon.com is actually a really good example of the opposite; they plan 5-7 years into the future, whereas most other companies measure "long-term" as 24 months. This is why Amazon went so long without a profit, but now is extremely profitable and the bane of places like Best Buy, who only planned for the short-term and now struggle for sales.
I STILL put quarters in video games, as does everyone I take to my local arcade, but I won't even put slugs into a redemption machine; those slugs would be better used doing what they're doing now, rusting in a huge pile in my shed.
An arcade operator would need to have enough starting capital to remain open for a good decade without a single customer in order to live long enough to gain the momentum required to eventually operate at a profit. That is a very long term requirement, and is not feasible for most operators.
These older games will never really get old. The technology will get old, the hardware will get old, but the gameplay of arcade games as a whole will never die. There will always be a need for people to have quick 'easy-come, easy-go' game experiences, there will always be a desire to leave the house, and there will always be a desire to beat the high score. The few arcades that can stick it out and slowly cater to a new generation will be those who succeed, and it will be a long, hard road for them before that success will be realized.