The way I see it, the charts are there to reflect popular music tastes and trends. How we listen to music has evolved drastically over the past decade or two. While Billboards/RIAA's rules might be controversial to some, you'd be losing a significant amount of important information by ignoring streaming. It simply has to be accounted for nowadays.
My two cents.
Yes, charts are there to reflect popular music tastes and trends. Yes, the way we listen to music has evolved, meaning streaming is much more important BUT sales are sales and streams are streams. They cannot be equated reliably (IMO).
The present situation is one where the inclusion of streaming in the main official chart in the UK (using a conversion factor to calculate equivalent sales) has caused confusion.
In the UK most people treat the 'official singles chart' (compiled by the 'Official Charts Company') as a sales chart still, but it really isn't. It's a combined chart and it is deeply flawed.
But there IS still an official sales chart:
http://www.officialcharts.com/charts/singles-sales-chart/
And an official streaming chart:
http://www.officialcharts.com/charts/audio-streaming-chart/
They are separate and that works well. We can figure out which single sold most, and which single streamed most. Fine.
The problem is when the two are combined into the main chart - that is what causes important information to be lost, at least in many chart reports.
Often the most important chart positions (i.e. Top10 or Top5) rely upon how much streaming contributes to the overall picture.
Up to January '17 the company divided the number of streams by 100 to calculate the number of equivalent sales. Now they divide by 150. That's a big change. If it happened weeks or months earlier (or weeks or months later) it changes artists' chart positions (drastically in some cases!). This proves my point.
If they had chosen another number, that too would change chart positions. We're in a situation where the OCC's conversion factor now dictates who has a chart #1 and who doesn't, and that figure can be changed by them at any time.
The #1 single sold and the #1 streamed single cannot really be debated, but the country's official #1 single (overall) is often determined by the conversion factor. So the current 'Official Singles Chart' - the one that determines who gets awarded a #1 single - only reflects the OCC's decision on the weighting between streams and sales, it doesn't necessarily report the nation's most popular single in an accurate way.
I suspect the same will be true (to a greater or lesser extent) on the US charts.