Evan Spiegel should have been fired after the frat emails surfaced. As for Clinkle, that's been around for years and hasn't produced jack shit because it's not even a real company-- just a scam.

However, I'd say that all these examples basically disprove your theory about them making it harder for "real" startups to compete. Webvan flamed out miserably, but that didn't stop Peapod (and now Instacart, Google Shopping Express, and Amazon Prime) from taking off. SnapChat didn't exactly hurt WhatsApp's chances. Cuil has had a negligible impact on DuckDuckGo - it just flamed out, pivoted beyond recognition, died, and the founder went back to her job at Google. Digg's death throes proved a huge boon for Reddit, and their audience started increasing massively.

As a startup founder, you are best off just ignoring the well-funded competitor who's doing everything wrong. Let them pave the path, legitimize the marketplace, pump millions of dollars in ad spending into the noosphere - and then quietly save your cash, talk to real customers, build the product that people actually want, and provide a breath of fresh air for the people that were burned by your celebrity dunce competitor.