These are really sector bets. Both VUG and especially QQQ are concentrated bets on the US technology sector. They are performing well because tech has done well recently.Finally is there or is there not consensus on the future of growth ETFs like VUG and QQQ?
They have done so well over the last decade I'm reluctant to just say good bye.
There is not consensus on the future growth prospects of these. These are essentially concentrated sector bets. I don't think that's a good way to invest. Themes like this tend to change over time. A hot sector becomes cold, and sometimes that lasts for a very long time.
Most of us think it's better to invest in more broadly diversified funds. The S&P 500 for example contains many different sectors and isn't just a bet on technology. So once tech weakens and another sector strengthens, you aren't ruined. It has less dramatically strong performance, but it has steadier performance over the years.
To see why betting on specific sectors is a bad idea, here are a few different sectors and their worst, longest lasting negative periods
Canadian energy (XEG) - negative for 12 years
American energy (XLE) - negative after 13 years
Canadian tech (XIT) - negative for 14 years
US financials (XLF) - negative for 14 years
QQQ was negative for 16 years after the dot com bubble
I think you'll see why QQQ (tech sector) is questionable as a long term investment. All of the above once had very hot performance. Once it turned cold, they were disastrous.
Until very recently, Canadian banks were also extremely hot, with amazingly strong performance. There are several ETFs that are very heavy in Canadian banks: XFN, XDV and many others. I suspect that this is another example of a sector that is going to turn into a poor long term performer. This will be disastrous for all the people (and there are a lot of them!) who chased the performance of Canadian banks, making it a high weight in their portfolios.