"Hands down the people who are most concerned about this trend are the angel investors."

Wrong. This is not an investor's problem. This is an entrepreneur's problem. The angels and VCs will shake this off as all of the combined seed dollars invested over the past couple of years are a relative fart in the wind compared to the greater startup investing arena, which doesn't become really capital-intensive until at least the Series A, and more often Series B stages.

It's the entrepreneurs who are (or at least should be) most concerned. Not the investors.

Edit: here's some cold, hard stats on the Seed VC phenomenon witnessed as of late: https://www.cbinsights.com/blog/venture-capital/seed-investm.... Seed investing continues to be a very real, growing trend, and yes - many startups will be left in the dust come Series A time.