Hmm. I don't find this shady. In the world of work (in the US at least) the flow of loyalty goes only one way -- from the employee to the employer, and screw the employee otherwise. (It didn't used to be this way, but such is a "market-based" work economy.) If you want to give 1000% (I'm not making a typo) only to be replaced at the drop of a hat by your employer, go right ahead, but I personally think such an attitude is extremely naive. No one but you is going to take care of yourself, and you are far best off knowing your limits and your goals, and planning accordingly.
You don't have to be dead wood, but only a less than hyper-willing-to-do-anything wood, to be less than utterly attractive to your employer. Frankly, few of us retain the ability to work like at maniac in our fifties, like we did in our thirties. So slow down and consider yourself as pacing yourself so you can last to fifty-five. It's the mature thing to do, and nothing shady about it. Personally, I applaud your ability to take the long view of your place in the work, and to not let yourself be manipulated into working yourself into a tizzy perpetually. Good luck.
