To the original question, "Are you wrong to be invested in individual stocks?" Absolutely not, there are some great opportunities out there and if you have the means and the motivation, why not take advantage of it? On the other hand, the original post indicates that you have little or no investment in index funds or any mutual funds. That is a mistake in my opinion, since as stated in the original post, it is very difficult for any single individual to closely follow more than 7-8 companies.
The bottom line, is that with only 7-8 companies, you are not very diversified, so a significant downturn or period of extended malaise in just a few of these stocks could have quite a negative impact on your overall returns, in which case, you would have been better off with an index fund. Now, there's no question that there will be periods where a 7-8 company portfolio will beat the market. The real question is whether your research and decision making is sufficient to avoid a major mistake for decades? I think the answer to this question is that the odds are not in your favor. Most market research tends to suggest that the odds of beating the market are on the order of 10% or less, however, mostly this applies to institutional investors. I suspect a disciplined small investor can probably increase these odds, perhaps even to the 30-40% level, in which case you do have a significant chance of beating the market long term, but the odds are still against you.
Now having said that, I want to repeat that to me, it makes a lot of sense to keep a portion of investments in stocks and even higher risk investments. I originally started investing in individual stocks through an Employee Purchase program at work, which gave extremely favorable terms. At some point, about ten years ago, the IRS cracked down on such programs, so when I changed employers I enrolled in the new program, but the terms were only marginally favorable and I'm not sure I really beat the market with the stock from this second employer.
Finally, in 2012, I struck out on my own and invested in individual stocks. Mostly, I picked banking stocks, as some had book values that far exceeded the share price and we seemed to be well into a recovery. I also started learning about and investing in options. I bought AMZN, which certainly didn't hurt, either. My returns have been phenomenal:
Portfolio S&P500
2012: 64.8% 15.9%
2013: 67.3% 32.4%
2014: 24.2% 13.8%
2015: 6.3% 1.3%
2016: -8.6% 11.9%
2017: 66.2% 21.9%
2018: 45.0% 9.3%
Now I'm under no illusion that I will be able to maintain such returns long-term. There's no question that I have taken on significant risk and have been rewarded handsomely. My approach to mitigating this risk is to remove a portion of the proceeds and roll it into index funds and bonds. Also, as market conditions become less favorable, I will need to be more aggressive about unwinding some of these investments. I particularly struggle with what to do with AMZN. Last year, when it topped $1K/share, I unloaded ~40%. In hindsight that was a mistake, although I would do it again just to reduce my market exposure.