I agree 100%. What this also means is that, because of these micro-domain specializations, unless a founder has either a lot of time or a lot of money, what they end up building is (usually, if the market opportunity is in the multi-billions) an advanced functional prototype wealthier companies can look at as bellwether to judge the scalable profitability they could generate through acquisition. There's still enormous space for web-based SMBs, but that's not what most people think of when they think "startup."