I enjoy bowl games and support the bowl system, especially as a Purdue fan. I love watching the games between two similar teams in different conferences.
However, if I was guaranteed to be a first or second round pick I would not play in a non-playoff game for the boilers. There is too much risk, and yes, they are a glorified exhibition game to generate money for the NCAA and the Universities. For most players it is a nice vacation to celebrate a decent season and get some cool gear. For the 1% exception, it makes no sense to have 10 extra practices and risk dropping your draft stock.
And for the record, the last time we played a meaningful game was Wisconsin in 2004. Or maybe Minnesota in 2005 when we still thought that team was good.