Expensive is relative to everyone - but people who say bitcoin is expensive are basically orienting themselves and comparing its price between then and now. In 2019 - someone with $4K could buy more than 1 btc - but now, $4K can only buy 0.041 btc. Maybe that's why many of them say bitcoin is expensive - they are always oriented towards past prices. But anyone who has money can always buy and accumulate regardless of how many satoshis they can buy with their money now. The point is only one - bitcoin can always be bought and not everyone will consider it too late.
There is another side to the coin, Bitcoin is becoming a heavier asset and every time it reaches a higher price, it becomes more difficult for it to grow due to the large capitalization of the asset. Yes, Bitcoin will most likely continue to grow in price, so buying it now may not be the worst idea, but perhaps in the coming years, it will not be able to grow more than several times. I only know one thing, that buying Bitcoin has always been a good idea, and in the future it will also grow, but perhaps not with such a profit as it was in the past.
Heavier asset to the fact that adaption level is growing and the demand goes higher especially that lots of people want to grab their own Bitcoin for investment purposes. Maybe some people may say that Bitcoin price is now expensive and thinking that they are late its because they are new to the scene. But if they could just realize that Bitcoin opportunities and growth level is not yet on its end point then provably that they would start to love accumulating Bitcoin.
Buying Bitcoin would never be a bad idea and so far data's prove it that people choose to hold Bitcoin always gains. So better buy Bitcoin and don't think about its late to buy it since they will just missed some good opportunities if they let those opportunity slip on their hands.