I don't understand this kind of thinking. You are on a board mostly full of informed TSLA investors. Most of us bought so much at lower levels that our portfolios would not be considered diversified or balanced. As the price rises, this situation (happily) becomes more pronounced. Our portfolios are more unbalanced than ever. Some of us can handle the portfolio volatility this encourages, others will re-balance. I haven't done any rebalancing with this rise because I know how that can dramatically impact future returns in a negative manner but I would be more likely to sell at these prices than buy. And not because I'm not confident it will rise much higher in the future.
Why would we buy even more as the price rises? My last purchase was at the $360 level.
Since 2017 I've transferred some investments to $TSLA and put any excess cash into $TSLA. Sometimes when I want to buy something I'll ask myself "would I rather have that widget or another couple $TSLA shares?", then go buy the shares. Well as I continue to work and bring in more money than I wish to spend, I have to invest it somewhere. Since I still don't know a place I'd rather put my money to work, I guess I'll still be buying $TSLA.