I still don't see why it had to be Bayern and only Bayern for him.
Well, probably several reasons for an established player like Lewa. Please note that I'm keeping strictly to the positives here for convenience and I'm aware that some of these positives can be found at other clubs too - so think of this as a total package.
1. Payment ranges from high to exorbitant and opportunities to earn performance-dependant bonuses are abundant. Wages get paid on schedule.
2. The club cares for his alumni, no matter how low one has fallen in the mean-time. Becoming a raging alcoholic like Gerd Müller, stealing barbiturates and burning your house down like Breno - the club helps you and finds you a job. Having played for Bayern is an annuity assurance.
3. Playing for Bayern is a significant advantage in the players track-record. It's a proof that the player can withstand the pressure on the absolute top-level and is used to being asked to give 105 % every matchday. Also an advantage when looking for a coach job in the future, be it with Bayern or with someone else.
4. Football on the international level is practically guarenteed which also means that the player can present himself on that stage to earn/keep the spot in the NT.
5. Bayern attach importance to a long-term orientated and sustainable development of the club which is also important to the player. A club/corporate philosophy leakes through from top to bottom.
6. A clear command structure. Nothing is worse for an employee than to find himself in an environment where everyone administers everything and nothing.
7. Top-notch personnel: Think of Rummenigge, Hoeneß, Sammer, Hopfner, Wacker, Dreesen etc. what you want, but this club is loaded from top to bottom with people who know their trade.
8. The team: The player is guarenteed to be surrounded by elite players which can complement his own ability or even further enhance it. Players are bought with a long-term perspective and the core of players mostly stay in the long run - the player doesn't find himself in a different environment every two years.