I would argue that Bowie is one of the top 5 most influential musicians of the past 50 years. Those five key 70s albums are the seeds that become so much of 90s music and beyond. Smashing Pumpkins built their entire shtick off Ziggy Stardust. So did the Pixies and many others. Young Americans with Luther Vandross set the style for tons of later crossover hits.
Watch the documentary Five Years with David Bowie on SHO. You'll love it.