@amirm - How come there is no ordered list option (1,2,3)? Or did I miss it?
Not saying I strongly agree or disagree either way, but here are my off-the-cuff thoughts on cons (we could make a similar list of pros):
1. Passive components are cheaper.
2. Passive components are likely to last longer and be more reliable over time. In an active speaker, any one failure (e.g. one amp) takes down the whole system, and consumers are unlikely to have suitable replacements around. With a passive speaker, if an amp dies, I may have another amp or channel I can use, particularly for an HT system. Of course if a driver dies, the speaker is down, active or passive.
3. Passive speakers do not require having an outlet near each speaker and associated power cord. Unless wireless, you still have to run a cable to the speaker, so a wash at best.
4. Active speakers still need a crossover somewhere, whether active or passive line-level. More cost, and greater if you go with a DSP-based approach for flexibility. DSP opens the option for greater flexibility, a mixed bag, since some customers can take advantage and some cannot/will not, plus the one who mistakenly (or not) totally trashes the performance (and perhaps the speaker) with bad programming.
5. Active speaker amplifiers must be designed for the listener farthest away so may be way over powered (and thus more costly, bulkier, etc.) for many listeners.
6. Speaker size and weight may increase when amplifiers and support circuits are added (may not matter, but a difference).
7. Historically users like buying separates, or having the option to buy separates, and "all-in-one" anything is looked down upon. Thank Marketing for that -- separates are always considered a step-up and the pinnacle of performance, right or wrong...
8. Makes it harder for users to upgrade. Modular designs, which should solve that issue, have not fared well in the past for various reasons including proprietary interfaces, higher cost for swappable components, and reduce reliability due to the additional connections.
9. Greater potential for ground loops and perhaps other noise due to distributed power (AC wall power) connections and longer line-level (or wireless) links (longer cables are unlikely to be an issue assuming competent design, but the potential problems do exist).
10. I couldn't think of another off-hand but didn't want to stop at an odd number.
FWIWFM - Don