Since the price of Bitcoin has been climbing and doesn't seem to be done since SegWit is upon us, would it now be worth it to mine Bitcoins?
After all, the block sizes and difficulty don't change until every 4 years, despite what the price may be.
If the price goes to $4000 or $5000, I suspect there will be a surge in mining activity. Just want to get thoughts from BitcoinTalk members before I make a conclusion.
Bitcoin has nearly always been worth mining, otherwise it wouldn't have miners would it? It just depends on your electricity rate. You also probably need to use the latest ASICs.
The block size NEVER changes unless there is a hard fork, which requires consensus. I suppose you mean block reward which halves every 210000 blocks. That is about 4 years.
The mining difficulty readjusts every 2016 blocks (which is about 2 weeks) so as to maintain a 10 minute block time. It has always been this way.
The total network hashing power (or mining activity as you call it) does not usually reflect price changes unless the price declines very steeply in a very short amount of time.
You may have other misconceptions about Bitcoin like the ones above, I'd suggest you Google and read stuff.
https://en.bitcoin.it is a very good learning source.