Google ads may be around for the next 10 more years...Policy may change that will weed out the small guys but I will recommend that you dont keep all your eggs in one basket and look for other Adsense alternative... From you have the internet you will always have advertising business opportunities...check this link for other Adsense alternative, so if Google kick you out or banned your account, you have other option of finding advertiser for your site.
Adsense can be around but have passed trough a lot of metamorphosis as the internet world is also not static.