Re: Why not web?
Some things make more sense as web apps, some as local applications.
For example, if you're creating and updating transactions in some central database - 100% of CRM, ERP, billing and payments - then a web app is now the best approach.
After all, if you can't reach (a shard of) the DB server you're not doing anything anyway, so you lose nothing and gain independence from any particular client OS.
If you're designing a building, then it does need to be local because you need the horsepower and latency will kill you inch by inch.
There is no One True Way. Pretending there is leads to death by a thousand cuts.